Code Style and Cleanups

src/Numerics.Tests/StatisticsTests/MCMCTests/MetropolisHastingsSamplerTests.cs

@@ -93,17 +93,5 @@ namespace MathNet.Numerics.UnitTests.StatisticsTests.McmcTests
 
             ms.Sample(5);
         }
-
-        /// <summary>
-        /// Set <c>null</c> RNG throws <c>ArgumentNullException</c>.
-        /// </summary>
-        [Test]
-        public void NullRandomNumberGenerator()
-        {
-            var random = MersenneTwister.Default;
-            var normal = new Normal(0.0, 1.0, random);
-            var ms = new MetropolisHastingsSampler<double>(0.2, normal.Density, (x, y) => Normal.PDF(x, 0.1, y), x => Normal.Sample(random, x, 0.1), 10);
-            Assert.That(() => ms.RandomSource = null, Throws.TypeOf<ArgumentNullException>());
-        }
     }
 }

src/Numerics.Tests/StatisticsTests/MCMCTests/MetropolisSamplerTests.cs

@@ -92,16 +92,5 @@ namespace MathNet.Numerics.UnitTests.StatisticsTests.McmcTests
 
             ms.Sample(5);
         }
-
-        /// <summary>
-        /// Set <c>null</c> RNG throws <c>ArgumentNullException</c>.
-        /// </summary>
-        [Test]
-        public void NullRandomNumberGenerator()
-        {
-            var normal = new Normal(0.0, 1.0);
-            var ms = new MetropolisSampler<double>(0.2, normal.Density, x => Normal.Sample(new Random(0), x, 0.1), 10);
-            Assert.That(() => ms.RandomSource = null, Throws.TypeOf<ArgumentNullException>());
-        }
     }
 }

src/Numerics.Tests/StatisticsTests/MCMCTests/RejectionSamplerTests.cs

@@ -97,16 +97,5 @@ namespace MathNet.Numerics.UnitTests.StatisticsTests.McmcTests
             var rs = new RejectionSampler<double>(x => Math.Pow(x, 1.7)*Math.Pow(1.0 - x, 5.3), x => Double.NegativeInfinity, uniform.Sample);
             Assert.That(() => rs.Sample(), Throws.ArgumentException);
         }
-
-        /// <summary>
-        /// Set <c>null</c> RNG throws <c>ArgumentNullException</c>.
-        /// </summary>
-        [Test]
-        public void NullRandomNumberGenerator()
-        {
-            var uniform = new ContinuousUniform(0.0, 1.0, new SystemRandomSource(1));
-            var rs = new RejectionSampler<double>(x => Math.Pow(x, 1.7)*Math.Pow(1.0 - x, 5.3), x => Double.NegativeInfinity, uniform.Sample);
-            Assert.That(() => rs.RandomSource = null, Throws.TypeOf<ArgumentNullException>());
-        }
     }
 }

src/Numerics/Compatibility.cs

@@ -1,4 +1,6 @@
-#if NETSTANDARD1_3
+using System.Globalization;
+
+#if NETSTANDARD1_3
 namespace MathNet.Numerics
 {
     using System;
@@ -156,3 +158,46 @@ namespace MathNet.Numerics
     }
 }
 #endif
+
+#if NET40
+namespace System.Runtime.CompilerServices
+{
+    internal class FormattableStringFactory
+    {
+        public static FormattableString Create(string format, params object[] args)
+        {
+            return new FormattableString(format, args);
+        }
+    }
+}
+
+namespace System
+{
+    internal class FormattableString
+    {
+        private readonly string format;
+        private readonly object[] args;
+
+        public FormattableString(string format, object[] args)
+        {
+            this.format = format;
+            this.args = args;
+        }
+
+        public static string Invariant(FormattableString messageFormat)
+        {
+            return messageFormat.ToString(CultureInfo.InvariantCulture);
+        }
+
+        public string ToString(IFormatProvider formatProvider)
+        {
+            return string.Format(formatProvider, format, args);
+        }
+
+        public override string ToString()
+        {
+            return string.Format(format, args);
+        }
+    }
+}
+#endif

src/Numerics/Complex32.cs

@@ -145,7 +145,7 @@ namespace MathNet.Numerics
         public float Real
         {
             [TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]
-            get { return _real; }
+            get => _real;
         }
 
         /// <summary>
@@ -155,7 +155,7 @@ namespace MathNet.Numerics
         public float Imaginary
         {
             [TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]
-            get { return _imag; }
+            get => _imag;
         }
 
         /// <summary>
@@ -171,7 +171,7 @@ namespace MathNet.Numerics
         {
             // NOTE: the special case for negative real numbers fixes negative-zero value behavior. Do not remove.
             [TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]
-            get { return _imag == 0f && _real < 0f ? (float)Constants.Pi : (float)Math.Atan2(_imag, _real); }
+            get => _imag == 0f && _real < 0f ? (float)Constants.Pi : (float)Math.Atan2(_imag, _real);
         }
 
         /// <summary>
@@ -212,10 +212,7 @@ namespace MathNet.Numerics
         /// Gets the squared magnitude (or squared absolute value) of a complex number.
         /// </summary>
         /// <returns>The squared magnitude of the current instance.</returns>
-        public float MagnitudeSquared
-        {
-            get { return (_real * _real) + (_imag * _imag); }
-        }
+        public float MagnitudeSquared => _real * _real + _imag * _imag;
 
         /// <summary>
         /// Gets the unity of this complex (same argument, but on the unit circle; exp(I*arg))

src/Numerics/Differentiation/FiniteDifferenceCoefficients.cs

@@ -49,7 +49,7 @@ namespace MathNet.Numerics.Differentiation
         /// </summary>
         public int Points
         {
-            get { return _points; }
+            get => _points;
             set
             {
                 CalculateCoefficients(value);

src/Numerics/Differentiation/NumericalDerivative.cs

@@ -72,7 +72,6 @@ namespace MathNet.Numerics.Differentiation
         double _stepSize = Math.Pow(2, -10);
         double _epsilon = Precision.PositiveMachineEpsilon;
         double _baseStepSize = Math.Pow(2, -26);
-        StepType _stepType = StepType.Relative;
         readonly FiniteDifferenceCoefficients _coefficients;
 
         /// <summary>
@@ -110,7 +109,7 @@ namespace MathNet.Numerics.Differentiation
         /// </remarks>
         public double StepSize
         {
-            get { return _stepSize; }
+            get => _stepSize;
             set
             {
                 //Base 2 yields more accurate results...
@@ -125,7 +124,7 @@ namespace MathNet.Numerics.Differentiation
         /// </summary>
         public double BaseStepSize
         {
-            get { return _baseStepSize; }
+            get => _baseStepSize;
             set
             {
                 //Base 2 yields more accurate results...
@@ -140,7 +139,7 @@ namespace MathNet.Numerics.Differentiation
         /// </summary>
         public double Epsilon
         {
-            get { return _epsilon; }
+            get => _epsilon;
             set
             {
                 //Base 2 yields more accurate results...
@@ -154,7 +153,7 @@ namespace MathNet.Numerics.Differentiation
         /// </summary>
         public int Center
         {
-            get { return _center; }
+            get => _center;
             set
             {
                 if (value >= _points || value < 0)
@@ -173,11 +172,7 @@ namespace MathNet.Numerics.Differentiation
         /// If set to relative, dx = (1+abs(x))*h^(2/(order+1)). This provides accurate results when
         /// h is approximately equal to the square-root of machine accuracy, epsilon.
         /// </summary>
-        public StepType StepType
-        {
-            get { return _stepType; }
-            set { _stepType = value; }
-        }
+        public StepType StepType { get; set; } = StepType.Relative;
 
         /// <summary>
         /// Evaluates the derivative of equidistant points using the finite difference method.

src/Numerics/Differentiation/NumericalHessian.cs

@@ -40,10 +40,7 @@ namespace MathNet.Numerics.Differentiation
         /// <summary>
         /// Number of function evaluations.
         /// </summary>
-        public int FunctionEvaluations
-        {
-            get { return _df.Evaluations; }
-        }
+        public int FunctionEvaluations => _df.Evaluations;
 
         private readonly NumericalDerivative _df;
 

src/Numerics/Differentiation/NumericalJacobian.cs

@@ -40,10 +40,7 @@ namespace MathNet.Numerics.Differentiation
         /// <summary>
         /// Number of function evaluations.
         /// </summary>
-        public int FunctionEvaluations
-        {
-            get { return _df.Evaluations; }
-        }
+        public int FunctionEvaluations => _df.Evaluations;
 
         private readonly NumericalDerivative _df;
 

src/Numerics/Distributions/SkewedGeneralizedError.cs

@@ -102,8 +102,8 @@ namespace MathNet.Numerics.Distributions
         /// </summary>
         public System.Random RandomSource
         {
-            get { return _random; }
-            set { _random = value ?? SystemRandomSource.Default; }
+            get => _random;
+            set => _random = value ?? SystemRandomSource.Default;
         }
 
         /// <summary>

src/Numerics/Integration/GaussKronrodRule.cs

@@ -48,46 +48,22 @@ namespace MathNet.Numerics.Integration
         /// <summary>
         /// Getter for the order.
         /// </summary>
-        public int Order
-        {
-            get
-            {
-                return gaussKronrodPoint.Order;
-            }
-        }
+        public int Order => gaussKronrodPoint.Order;
 
         /// <summary>
         /// Getter that returns a clone of the array containing the Kronrod abscissas.
         /// </summary>
-        public double[] KronrodAbscissas
-        {
-            get
-            {
-                return gaussKronrodPoint.Abscissas.Clone() as double[];
-            }
-        }
+        public double[] KronrodAbscissas => gaussKronrodPoint.Abscissas.Clone() as double[];
 
         /// <summary>
         /// Getter that returns a clone of the array containing the Kronrod weights.
         /// </summary>
-        public double[] KronrodWeights
-        {
-            get
-            {
-                return gaussKronrodPoint.Weights.Clone() as double[];
-            }
-        }
+        public double[] KronrodWeights => gaussKronrodPoint.Weights.Clone() as double[];
 
         /// <summary>
         /// Getter that returns a clone of the array containing the Gauss weights.
         /// </summary>
-        public double[] GaussWeights
-        {
-            get
-            {
-                return gaussKronrodPoint.SecondWeights.Clone() as double[];
-            }
-        }
+        public double[] GaussWeights => gaussKronrodPoint.SecondWeights.Clone() as double[];
 
         public GaussKronrodRule(int order)
         {
@@ -107,7 +83,7 @@ namespace MathNet.Numerics.Integration
         /// <param name="order">The number of Gauss-Kronrod points. Pre-computed for 15, 21, 31, 41, 51 and 61 points</param>
         public static double Integrate(Func<double, double> f, double intervalBegin, double intervalEnd, out double error, out double L1Norm, double targetRelativeError = 1E-10, int maximumDepth = 15, int order = 15)
         {
-            // Formula used for variable subsitution from 
+            // Formula used for variable subsitution from
             // 1. Shampine, L. F. (2008). Vectorized adaptive quadrature in MATLAB. Journal of Computational and Applied Mathematics, 211(2), 131-140.
             // 2. quadgk.m, GNU Octave
 
@@ -193,7 +169,7 @@ namespace MathNet.Numerics.Integration
         /// <returns></returns>
         public static Complex ContourIntegrate(Func<double, Complex> f, double intervalBegin, double intervalEnd, out double error, out double L1Norm, double targetRelativeError = 1E-10, int maximumDepth = 15, int order = 15)
         {
-            // Formula used for variable subsitution from 
+            // Formula used for variable subsitution from
             // 1. Shampine, L. F. (2008). Vectorized adaptive quadrature in MATLAB. Journal of Computational and Applied Mathematics, 211(2), 131-140.
             // 2. quadgk.m, GNU Octave
 

src/Numerics/Integration/GaussLegendreRule.cs

@@ -64,13 +64,7 @@ namespace MathNet.Numerics.Integration
         /// <summary>
         /// Getter that returns a clone of the array containing the abscissas.
         /// </summary>
-        public double[] Abscissas
-        {
-            get
-            {
-                return _gaussLegendrePoint.Abscissas.Clone() as double[];
-            }
-        }
+        public double[] Abscissas => _gaussLegendrePoint.Abscissas.Clone() as double[];
 
         /// <summary>
         /// Getter for the ith weight.
@@ -85,46 +79,22 @@ namespace MathNet.Numerics.Integration
         /// <summary>
         /// Getter that returns a clone of the array containing the weights.
         /// </summary>
-        public double[] Weights
-        {
-            get
-            {
-                return _gaussLegendrePoint.Weights.Clone() as double[];
-            }
-        }
+        public double[] Weights => _gaussLegendrePoint.Weights.Clone() as double[];
 
         /// <summary>
         /// Getter for the order.
         /// </summary>
-        public int Order
-        {
-            get
-            {
-                return _gaussLegendrePoint.Order;
-            }
-        }
+        public int Order => _gaussLegendrePoint.Order;
 
         /// <summary>
         /// Getter for the InvervalBegin.
         /// </summary>
-        public double IntervalBegin
-        {
-            get
-            {
-                return _gaussLegendrePoint.IntervalBegin;
-            }
-        }
+        public double IntervalBegin => _gaussLegendrePoint.IntervalBegin;
 
         /// <summary>
         /// Getter for the InvervalEnd.
         /// </summary>
-        public double IntervalEnd
-        {
-            get
-            {
-                return _gaussLegendrePoint.IntervalEnd;
-            }
-        }
+        public double IntervalEnd => _gaussLegendrePoint.IntervalEnd;
 
         /// <summary>
         /// Approximates a definite integral using an Nth order Gauss-Legendre rule.

src/Numerics/Interpolation/Barycentric.cs

@@ -254,18 +254,12 @@ namespace MathNet.Numerics.Interpolation
         /// <summary>
         /// Gets a value indicating whether the algorithm supports differentiation (interpolated derivative).
         /// </summary>
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return false; }
-        }
+        bool IInterpolation.SupportsDifferentiation => false;
 
         /// <summary>
         /// Gets a value indicating whether the algorithm supports integration (interpolated quadrature).
         /// </summary>
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return false; }
-        }
+        bool IInterpolation.SupportsIntegration => false;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/Interpolation/BulirschStoerRationalInterpolation.cs

@@ -100,18 +100,12 @@ namespace MathNet.Numerics.Interpolation
         /// <summary>
         /// Gets a value indicating whether the algorithm supports differentiation (interpolated derivative).
         /// </summary>
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return false; }
-        }
+        bool IInterpolation.SupportsDifferentiation => false;
 
         /// <summary>
         /// Gets a value indicating whether the algorithm supports integration (interpolated quadrature).
         /// </summary>
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return false; }
-        }
+        bool IInterpolation.SupportsIntegration => false;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/Interpolation/CubicSpline.cs

@@ -434,18 +434,12 @@ namespace MathNet.Numerics.Interpolation
         /// <summary>
         /// Gets a value indicating whether the algorithm supports differentiation (interpolated derivative).
         /// </summary>
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsDifferentiation => true;
 
         /// <summary>
         /// Gets a value indicating whether the algorithm supports integration (interpolated quadrature).
         /// </summary>
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsIntegration => true;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/Interpolation/LinearSpline.cs

@@ -117,18 +117,12 @@ namespace MathNet.Numerics.Interpolation
         /// <summary>
         /// Gets a value indicating whether the algorithm supports differentiation (interpolated derivative).
         /// </summary>
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsDifferentiation => true;
 
         /// <summary>
         /// Gets a value indicating whether the algorithm supports integration (interpolated quadrature).
         /// </summary>
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsIntegration => true;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/Interpolation/LogLinear.cs

@@ -110,18 +110,12 @@ namespace MathNet.Numerics.Interpolation
         /// <summary>
         /// Gets a value indicating whether the algorithm supports differentiation (interpolated derivative).
         /// </summary>
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsDifferentiation => true;
 
         /// <summary>
         /// Gets a value indicating whether the algorithm supports integration (interpolated quadrature).
         /// </summary>
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return false; }
-        }
+        bool IInterpolation.SupportsIntegration => false;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/Interpolation/NevillePolynomialInterpolation.cs

@@ -113,18 +113,12 @@ namespace MathNet.Numerics.Interpolation
         /// <summary>
         /// Gets a value indicating whether the algorithm supports differentiation (interpolated derivative).
         /// </summary>
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsDifferentiation => true;
 
         /// <summary>
         /// Gets a value indicating whether the algorithm supports integration (interpolated quadrature).
         /// </summary>
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return false; }
-        }
+        bool IInterpolation.SupportsIntegration => false;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/Interpolation/QuadraticSpline.cs

@@ -70,18 +70,12 @@ namespace MathNet.Numerics.Interpolation
         /// <summary>
         /// Gets a value indicating whether the algorithm supports differentiation (interpolated derivative).
         /// </summary>
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsDifferentiation => true;
 
         /// <summary>
         /// Gets a value indicating whether the algorithm supports integration (interpolated quadrature).
         /// </summary>
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsIntegration => true;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/Interpolation/StepInterpolation.cs

@@ -97,15 +97,9 @@ namespace MathNet.Numerics.Interpolation
             return InterpolateInplace(x.ToArray(), y.ToArray());
         }
 
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsDifferentiation => true;
 
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return true; }
-        }
+        bool IInterpolation.SupportsIntegration => true;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/Interpolation/TransformedInterpolation.cs

@@ -119,18 +119,12 @@ namespace MathNet.Numerics.Interpolation
         /// <summary>
         /// Gets a value indicating whether the algorithm supports differentiation (interpolated derivative).
         /// </summary>
-        bool IInterpolation.SupportsDifferentiation
-        {
-            get { return false; }
-        }
+        bool IInterpolation.SupportsDifferentiation => false;
 
         /// <summary>
         /// Gets a value indicating whether the algorithm supports integration (interpolated quadrature).
         /// </summary>
-        bool IInterpolation.SupportsIntegration
-        {
-            get { return false; }
-        }
+        bool IInterpolation.SupportsIntegration => false;
 
         /// <summary>
         /// Interpolate at point t.

src/Numerics/LinearAlgebra/Builder.cs

@@ -39,15 +39,9 @@ namespace MathNet.Numerics.LinearAlgebra.Double
 {
     internal class MatrixBuilder : MatrixBuilder<double>
     {
-        public override double Zero
-        {
-            get { return 0d; }
-        }
+        public override double Zero => 0d;
 
-        public override double One
-        {
-            get { return 1d; }
-        }
+        public override double One => 1d;
 
         public override Matrix<double> Dense(DenseColumnMajorMatrixStorage<double> storage)
         {
@@ -83,15 +77,9 @@ namespace MathNet.Numerics.LinearAlgebra.Double
 
     internal class VectorBuilder : VectorBuilder<double>
     {
-        public override double Zero
-        {
-            get { return 0d; }
-        }
+        public override double Zero => 0d;
 
-        public override double One
-        {
-            get { return 1d; }
-        }
+        public override double One => 1d;
 
         public override Vector<double> Dense(DenseVectorStorage<double> storage)
         {
@@ -114,15 +102,9 @@ namespace MathNet.Numerics.LinearAlgebra.Single
 {
     internal class MatrixBuilder : MatrixBuilder<float>
     {
-        public override float Zero
-        {
-            get { return 0f; }
-        }
+        public override float Zero => 0f;
 
-        public override float One
-        {
-            get { return 1f; }
-        }
+        public override float One => 1f;
 
         public override Matrix<float> Dense(DenseColumnMajorMatrixStorage<float> storage)
         {
@@ -158,15 +140,9 @@ namespace MathNet.Numerics.LinearAlgebra.Single
 
     internal class VectorBuilder : VectorBuilder<float>
     {
-        public override float Zero
-        {
-            get { return 0f; }
-        }
+        public override float Zero => 0f;
 
-        public override float One
-        {
-            get { return 1f; }
-        }
+        public override float One => 1f;
 
         public override Vector<float> Dense(DenseVectorStorage<float> storage)
         {
@@ -191,15 +167,9 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
 
     internal class MatrixBuilder : MatrixBuilder<Complex>
     {
-        public override Complex Zero
-        {
-            get { return Complex.Zero; }
-        }
+        public override Complex Zero => Complex.Zero;
 
-        public override Complex One
-        {
-            get { return Complex.One; }
-        }
+        public override Complex One => Complex.One;
 
         public override Matrix<Complex> Dense(DenseColumnMajorMatrixStorage<Complex> storage)
         {
@@ -235,15 +205,9 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
 
     internal class VectorBuilder : VectorBuilder<Complex>
     {
-        public override Complex Zero
-        {
-            get { return Complex.Zero; }
-        }
+        public override Complex Zero => Complex.Zero;
 
-        public override Complex One
-        {
-            get { return Complex.One; }
-        }
+        public override Complex One => Complex.One;
 
         public override Vector<Complex> Dense(DenseVectorStorage<Complex> storage)
         {
@@ -266,15 +230,9 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
 {
     internal class MatrixBuilder : MatrixBuilder<Numerics.Complex32>
     {
-        public override Numerics.Complex32 Zero
-        {
-            get { return Numerics.Complex32.Zero; }
-        }
+        public override Numerics.Complex32 Zero => Numerics.Complex32.Zero;
 
-        public override Numerics.Complex32 One
-        {
-            get { return Numerics.Complex32.One; }
-        }
+        public override Numerics.Complex32 One => Numerics.Complex32.One;
 
         public override Matrix<Numerics.Complex32> Dense(DenseColumnMajorMatrixStorage<Numerics.Complex32> storage)
         {
@@ -310,15 +268,9 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
 
     internal class VectorBuilder : VectorBuilder<Numerics.Complex32>
     {
-        public override Numerics.Complex32 Zero
-        {
-            get { return Numerics.Complex32.Zero; }
-        }
+        public override Numerics.Complex32 Zero => Numerics.Complex32.Zero;
 
-        public override Numerics.Complex32 One
-        {
-            get { return Numerics.Complex32.One; }
-        }
+        public override Numerics.Complex32 One => Numerics.Complex32.One;
 
         public override Vector<Numerics.Complex32> Dense(DenseVectorStorage<Numerics.Complex32> storage)
         {
@@ -364,16 +316,11 @@ namespace MathNet.Numerics.LinearAlgebra
         {
             if (storage == null) throw new ArgumentNullException(nameof(storage));
 
-            var dense = storage as DenseColumnMajorMatrixStorage<T>;
-            if (dense != null) return Dense(dense);
-
-            var sparse = storage as SparseCompressedRowMatrixStorage<T>;
-            if (sparse != null) return Sparse(sparse);
+            if (storage is DenseColumnMajorMatrixStorage<T> dense) return Dense(dense);
+            if (storage is SparseCompressedRowMatrixStorage<T> sparse) return Sparse(sparse);
+            if (storage is DiagonalMatrixStorage<T> diagonal) return Diagonal(diagonal);
 
-            var diagonal = storage as DiagonalMatrixStorage<T>;
-            if (diagonal != null) return Diagonal(diagonal);
-
-            throw new NotSupportedException(string.Format("Matrix storage type '{0}' is not supported. Only DenseColumnMajorMatrixStorage, SparseCompressedRowMatrixStorage and DiagonalMatrixStorage are supported as this point.", storage.GetType().Name));
+            throw new NotSupportedException(FormattableString.Invariant($"Matrix storage type '{storage.GetType().Name}' is not supported. Only DenseColumnMajorMatrixStorage, SparseCompressedRowMatrixStorage and DiagonalMatrixStorage are supported as this point."));
         }
 
         /// <summary>
@@ -1329,13 +1276,10 @@ namespace MathNet.Numerics.LinearAlgebra
         {
             if (storage == null) throw new ArgumentNullException(nameof(storage));
 
-            var dense = storage as DenseVectorStorage<T>;
-            if (dense != null) return Dense(dense);
-
-            var sparse = storage as SparseVectorStorage<T>;
-            if (sparse != null) return Sparse(sparse);
+            if (storage is DenseVectorStorage<T> dense) return Dense(dense);
+            if (storage is SparseVectorStorage<T> sparse) return Sparse(sparse);
 
-            throw new NotSupportedException(string.Format("Vector storage type '{0}' is not supported. Only DenseVectorStorage and SparseVectorStorage are supported as this point.", storage.GetType().Name));
+            throw new NotSupportedException(FormattableString.Invariant($"Vector storage type '{storage.GetType().Name}' is not supported. Only DenseVectorStorage and SparseVectorStorage are supported as this point."));
         }
 
         /// <summary>
@@ -1603,7 +1547,7 @@ namespace MathNet.Numerics.LinearAlgebra
                     (VectorBuilder<T>)(object)new Single.VectorBuilder());
             }
 
-            throw new NotSupportedException(string.Format("Matrices and vectors of type '{0}' are not supported. Only Double, Single, Complex or Complex32 are supported at this point.", typeof(T).Name));
+            throw new NotSupportedException(FormattableString.Invariant($"Matrices and vectors of type '{typeof(T).Name}' are not supported. Only Double, Single, Complex or Complex32 are supported at this point."));
         }
 
         public static void Register(MatrixBuilder<T> matrixBuilder, VectorBuilder<T> vectorBuilder)
@@ -1611,14 +1555,8 @@ namespace MathNet.Numerics.LinearAlgebra
             _singleton = new Lazy<Tuple<MatrixBuilder<T>, VectorBuilder<T>>>(() => new Tuple<MatrixBuilder<T>, VectorBuilder<T>>(matrixBuilder, vectorBuilder));
         }
 
-        public static MatrixBuilder<T> Matrix
-        {
-            get { return _singleton.Value.Item1; }
-        }
+        public static MatrixBuilder<T> Matrix => _singleton.Value.Item1;
 
-        public static VectorBuilder<T> Vector
-        {
-            get { return _singleton.Value.Item2; }
-        }
+        public static VectorBuilder<T> Vector => _singleton.Value.Item2;
     }
 }

src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs

@@ -395,10 +395,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// Gets the matrix's data.
         /// </summary>
         /// <value>The matrix's data.</value>
-        public Complex[] Values
-        {
-            get { return _values; }
-        }
+        public Complex[] Values => _values;
 
         /// <summary>Calculates the induced L1 norm of this matrix.</summary>
         /// <returns>The maximum absolute column sum of the matrix.</returns>
@@ -427,8 +424,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the negation.</param>
         protected override void DoNegate(Matrix<Complex> result)
         {
-            var denseResult = result as DenseMatrix;
-            if (denseResult != null)
+            if (result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(-1, _values, denseResult._values);
                 return;
@@ -443,8 +439,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the conjugation.</param>
         protected override void DoConjugate(Matrix<Complex> result)
         {
-            var denseResult = result as DenseMatrix;
-            if (denseResult != null)
+            if (result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.ConjugateArray(_values, denseResult._values);
                 return;
@@ -487,17 +482,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         protected override void DoAdd(Matrix<Complex> other, Matrix<Complex> result)
         {
             // dense + dense = dense
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            var denseResult = result.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            if (denseOther != null && denseResult != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex> denseOther && result.Storage is DenseColumnMajorMatrixStorage<Complex> denseResult)
             {
                 LinearAlgebraControl.Provider.AddArrays(_values, denseOther.Data, denseResult.Data);
                 return;
             }
 
             // dense + diagonal = any
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex> diagonalOther)
             {
                 Storage.CopyToUnchecked(result.Storage, ExistingData.Clear);
                 var diagonal = diagonalOther.Data;
@@ -543,17 +535,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         protected override void DoSubtract(Matrix<Complex> other, Matrix<Complex> result)
         {
             // dense + dense = dense
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            var denseResult = result.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            if (denseOther != null && denseResult != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex> denseOther && result.Storage is DenseColumnMajorMatrixStorage<Complex> denseResult)
             {
                 LinearAlgebraControl.Provider.SubtractArrays(_values, denseOther.Data, denseResult.Data);
                 return;
             }
 
             // dense + diagonal = matrix
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex> diagonalOther)
             {
                 CopyTo(result);
                 var diagonal = diagonalOther.Data;
@@ -619,9 +608,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiply(
                     _values,
@@ -634,8 +621,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(ColumnCount, other.ColumnCount);
@@ -665,9 +651,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeAndMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.DontTranspose,
@@ -684,8 +668,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(ColumnCount, other.RowCount);
@@ -715,9 +698,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeAndMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.DontTranspose,
@@ -734,8 +715,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var conjugateDiagonal = new Complex[diagonal.Length];
@@ -771,9 +751,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Vector<Complex> rightSide, Vector<Complex> result)
         {
-            var denseRight = rightSide as DenseVector;
-            var denseResult = result as DenseVector;
-            if (denseRight != null && denseResult != null)
+            if (rightSide is DenseVector denseRight && result is DenseVector denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.Transpose,
@@ -800,9 +778,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeThisAndMultiply(Vector<Complex> rightSide, Vector<Complex> result)
         {
-            var denseRight = rightSide as DenseVector;
-            var denseResult = result as DenseVector;
-            if (denseRight != null && denseResult != null)
+            if (rightSide is DenseVector denseRight && result is DenseVector denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.ConjugateTranspose,
@@ -829,9 +805,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.Transpose,
@@ -848,8 +822,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(RowCount, other.ColumnCount);
@@ -880,9 +853,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeThisAndMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.ConjugateTranspose,
@@ -899,8 +870,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(RowCount, other.ColumnCount);

src/Numerics/LinearAlgebra/Complex/DenseVector.cs

@@ -162,10 +162,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// Gets the vector's data.
         /// </summary>
         /// <value>The vector's data.</value>
-        public Complex[] Values
-        {
-            get { return _values; }
-        }
+        public Complex[] Values => _values;
 
         /// <summary>
         /// Returns a reference to the internal data structure.

src/Numerics/LinearAlgebra/Complex/DiagonalMatrix.cs

@@ -192,8 +192,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the negation.</param>
         protected override void DoNegate(Matrix<Complex> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(-1, _data, diagResult._data);
                 return;
@@ -212,8 +211,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the conjugation.</param>
         protected override void DoConjugate(Matrix<Complex> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ConjugateArray(_data, diagResult._data);
                 return;
@@ -235,9 +233,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         protected override void DoAdd(Matrix<Complex> other, Matrix<Complex> result)
         {
             // diagonal + diagonal = diagonal
-            var diagOther = other as DiagonalMatrix;
-            var diagResult = result as DiagonalMatrix;
-            if (diagOther != null && diagResult != null)
+            if (other is DiagonalMatrix diagOther && result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.AddArrays(_data, diagOther._data, diagResult._data);
                 return;
@@ -259,9 +255,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         protected override void DoSubtract(Matrix<Complex> other, Matrix<Complex> result)
         {
             // diagonal - diagonal = diagonal
-            var diagOther = other as DiagonalMatrix;
-            var diagResult = result as DiagonalMatrix;
-            if (diagOther != null && diagResult != null)
+            if (other is DiagonalMatrix diagOther && result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.SubtractArrays(_data, diagOther._data, diagResult._data);
                 return;
@@ -320,9 +314,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
 
             if (d == ColumnCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<Complex>;
-                var denseResult = result.Storage as DenseVectorStorage<Complex>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<Complex> denseOther && result.Storage is DenseVectorStorage<Complex> denseResult)
                 {
                     LinearAlgebraControl.Provider.PointWiseMultiplyArrays(_data, denseOther.Data, denseResult.Data);
                     return;
@@ -342,9 +334,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex[diagonalResult._data.Length];
                 var otherDataCopy = new Complex[diagonalResult._data.Length];
@@ -354,8 +344,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -395,9 +384,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeAndMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex[diagonalResult._data.Length];
                 var otherDataCopy = new Complex[diagonalResult._data.Length];
@@ -407,8 +394,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -439,9 +425,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeAndMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex[diagonalResult._data.Length];
                 var otherDataCopy = new Complex[diagonalResult._data.Length];
@@ -453,8 +437,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -485,9 +468,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex[diagonalResult._data.Length];
                 var otherDataCopy = new Complex[diagonalResult._data.Length];
@@ -497,8 +478,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -538,9 +518,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeThisAndMultiply(Matrix<Complex> other, Matrix<Complex> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex[diagonalResult._data.Length];
                 var otherDataCopy = new Complex[diagonalResult._data.Length];
@@ -552,8 +530,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex> denseOther)
             {
                 var dense = denseOther.Data;
                 var conjugateDiagonal = new Complex[_data.Length];
@@ -598,9 +575,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
 
             if (d == RowCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<Complex>;
-                var denseResult = result.Storage as DenseVectorStorage<Complex>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<Complex> denseOther && result.Storage is DenseVectorStorage<Complex> denseResult)
                 {
                     LinearAlgebraControl.Provider.PointWiseMultiplyArrays(_data, denseOther.Data, denseResult.Data);
                     return;
@@ -628,9 +603,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
 
             if (d == RowCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<Complex>;
-                var denseResult = result.Storage as DenseVectorStorage<Complex>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<Complex> denseOther && result.Storage is DenseVectorStorage<Complex> denseResult)
                 {
                     // TODO: merge/MulByConj
                     LinearAlgebraControl.Provider.ConjugateArray(_data, denseResult.Data);
@@ -658,8 +631,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(1.0/divisor, _data, diagResult._data);
                 return;
@@ -679,8 +651,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">The matrix to store the result of the division.</param>
         protected override void DoDivideByThis(Complex dividend, Matrix<Complex> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 var resultData = diagResult._data;
                 CommonParallel.For(0, _data.Length, 4096, (a, b) =>

src/Numerics/LinearAlgebra/Complex/Factorization/Svd.cs

@@ -74,13 +74,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Factorization
         /// Gets the two norm of the <see cref="Matrix{T}"/>.
         /// </summary>
         /// <returns>The 2-norm of the <see cref="Matrix{T}"/>.</returns>
-        public override double L2Norm
-        {
-            get
-            {
-                return S[0].Magnitude;
-            }
-        }
+        public override double L2Norm => S[0].Magnitude;
 
         /// <summary>
         /// Gets the condition number <b>max(S) / min(S)</b>

src/Numerics/LinearAlgebra/Complex/Solvers/GpBiCg.cs

@@ -82,7 +82,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers
         /// </summary>
         public int NumberOfBiCgStabSteps
         {
-            get { return _numberOfBiCgStabSteps; }
+            get => _numberOfBiCgStabSteps;
 
             set
             {
@@ -101,7 +101,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers
         /// </summary>
         public int NumberOfGpBiCgSteps
         {
-            get { return _numberOfGpbiCgSteps; }
+            get => _numberOfGpbiCgSteps;
 
             set
             {

src/Numerics/LinearAlgebra/Complex/Solvers/ILUTPPreconditioner.cs

@@ -162,7 +162,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double FillLevel
         {
-            get { return _fillLevel; }
+            get => _fillLevel;
             set
             {
                 if (value < 0)
@@ -193,7 +193,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double DropTolerance
         {
-            get { return _dropTolerance; }
+            get => _dropTolerance;
             set
             {
                 if (value < 0)
@@ -226,7 +226,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double PivotTolerance
         {
-            get { return _pivotTolerance; }
+            get => _pivotTolerance;
             set
             {
                 if (value < 0)

src/Numerics/LinearAlgebra/Complex/Solvers/MlkBiCgStab.cs

@@ -89,7 +89,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers
         public int NumberOfStartingVectors
         {
             [DebuggerStepThrough]
-            get { return _numberOfStartingVectors; }
+            get => _numberOfStartingVectors;
 
             [DebuggerStepThrough]
             set
@@ -118,7 +118,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers
         public IList<Vector<Complex>> StartingVectors
         {
             [DebuggerStepThrough]
-            get { return _startingVectors; }
+            get => _startingVectors;
 
             [DebuggerStepThrough]
             set

src/Numerics/LinearAlgebra/Complex/SparseMatrix.cs

@@ -53,10 +53,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// Gets the number of non zero elements in the matrix.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int NonZerosCount
-        {
-            get { return _storage.ValueCount; }
-        }
+        public int NonZerosCount => _storage.ValueCount;
 
         /// <summary>
         /// Create a new sparse matrix straight from an initialized matrix storage instance.
@@ -890,8 +887,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex>;
-            if (diagonalOther != null && sparseResult != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex> diagonalOther && sparseResult != null)
             {
                 var diagonal = diagonalOther.Data;
                 if (other.ColumnCount == other.RowCount)
@@ -912,8 +908,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
             var rowPointers = _storage.RowPointers;
             var columnIndices = _storage.ColumnIndices;
             var values = _storage.Values;
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex> denseOther)
             {
                 // in this case we can directly address the underlying data-array
                 for (var row = 0; row < RowCount; row++)
@@ -1547,7 +1542,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
 
         public override string ToTypeString()
         {
-            return string.Format("SparseMatrix {0}x{1}-Complex {2:P2} Filled", RowCount, ColumnCount, NonZerosCount / (RowCount * (double)ColumnCount));
+            return FormattableString.Invariant($"SparseMatrix {RowCount}x{ColumnCount}-Complex {NonZerosCount / (RowCount * (double) ColumnCount):P2} Filled");
         }
     }
  }

src/Numerics/LinearAlgebra/Complex/SparseVector.cs

@@ -52,10 +52,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// Gets the number of non zero elements in the vector.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int NonZerosCount
-        {
-            get { return _storage.ValueCount; }
-        }
+        public int NonZerosCount => _storage.ValueCount;
 
         /// <summary>
         /// Create a new sparse vector straight from an initialized vector storage instance.
@@ -404,8 +401,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <param name="result">Target vector</param>
         protected override void DoConjugate(Vector<Complex> result)
         {
-            var sparseResult = result as SparseVector;
-            if (sparseResult != null)
+            if (result is SparseVector sparseResult)
             {
                 if (!ReferenceEquals(this, result))
                 {
@@ -931,7 +927,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
 
         public override string ToTypeString()
         {
-            return string.Format("SparseVector {0}-Complex {1:P2} Filled", Count, NonZerosCount / (double)Count);
+            return FormattableString.Invariant($"SparseVector {Count}-Complex {NonZerosCount / (double) Count:P2} Filled");
         }
     }
 }

src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs

@@ -395,10 +395,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// Gets the matrix's data.
         /// </summary>
         /// <value>The matrix's data.</value>
-        public Complex32[] Values
-        {
-            get { return _values; }
-        }
+        public Complex32[] Values => _values;
 
         /// <summary>Calculates the induced L1 norm of this matrix.</summary>
         /// <returns>The maximum absolute column sum of the matrix.</returns>
@@ -427,8 +424,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the negation.</param>
         protected override void DoNegate(Matrix<Complex32> result)
         {
-            var denseResult = result as DenseMatrix;
-            if (denseResult != null)
+            if (result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(-1, _values, denseResult._values);
                 return;
@@ -443,8 +439,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the conjugation.</param>
         protected override void DoConjugate(Matrix<Complex32> result)
         {
-            var denseResult = result as DenseMatrix;
-            if (denseResult != null)
+            if (result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.ConjugateArray(_values, denseResult._values);
                 return;
@@ -487,17 +482,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         protected override void DoAdd(Matrix<Complex32> other, Matrix<Complex32> result)
         {
             // dense + dense = dense
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            var denseResult = result.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            if (denseOther != null && denseResult != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex32> denseOther && result.Storage is DenseColumnMajorMatrixStorage<Complex32> denseResult)
             {
                 LinearAlgebraControl.Provider.AddArrays(_values, denseOther.Data, denseResult.Data);
                 return;
             }
 
             // dense + diagonal = any
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex32> diagonalOther)
             {
                 Storage.CopyToUnchecked(result.Storage, ExistingData.Clear);
                 var diagonal = diagonalOther.Data;
@@ -543,17 +535,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         protected override void DoSubtract(Matrix<Complex32> other, Matrix<Complex32> result)
         {
             // dense + dense = dense
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            var denseResult = result.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            if (denseOther != null && denseResult != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex32> denseOther && result.Storage is DenseColumnMajorMatrixStorage<Complex32> denseResult)
             {
                 LinearAlgebraControl.Provider.SubtractArrays(_values, denseOther.Data, denseResult.Data);
                 return;
             }
 
             // dense + diagonal = matrix
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex32> diagonalOther)
             {
                 CopyTo(result);
                 var diagonal = diagonalOther.Data;
@@ -619,9 +608,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiply(
                     _values,
@@ -634,8 +621,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex32> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(ColumnCount, other.ColumnCount);
@@ -665,9 +651,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeAndMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.DontTranspose,
@@ -684,8 +668,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex32> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(ColumnCount, other.RowCount);
@@ -715,9 +698,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeAndMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.DontTranspose,
@@ -734,8 +715,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex32> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var conjugateDiagonal = new Complex32[diagonal.Length];
@@ -802,9 +782,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeThisAndMultiply(Vector<Complex32> rightSide, Vector<Complex32> result)
         {
-            var denseRight = rightSide as DenseVector;
-            var denseResult = result as DenseVector;
-            if (denseRight != null && denseResult != null)
+            if (rightSide is DenseVector denseRight && result is DenseVector denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.ConjugateTranspose,
@@ -831,9 +809,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.Transpose,
@@ -850,8 +826,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex32> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(RowCount, other.ColumnCount);
@@ -882,9 +857,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeThisAndMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.ConjugateTranspose,
@@ -901,8 +874,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex32> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(RowCount, other.ColumnCount);

src/Numerics/LinearAlgebra/Complex32/DenseVector.cs

@@ -162,10 +162,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// Gets the vector's data.
         /// </summary>
         /// <value>The vector's data.</value>
-        public Complex32[] Values
-        {
-            get { return _values; }
-        }
+        public Complex32[] Values => _values;
 
         /// <summary>
         /// Returns a reference to the internal data structure.

src/Numerics/LinearAlgebra/Complex32/DiagonalMatrix.cs

@@ -192,8 +192,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the negation.</param>
         protected override void DoNegate(Matrix<Complex32> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(-1, _data, diagResult._data);
                 return;
@@ -212,8 +211,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the conjugation.</param>
         protected override void DoConjugate(Matrix<Complex32> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ConjugateArray(_data, diagResult._data);
                 return;
@@ -235,9 +233,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         protected override void DoAdd(Matrix<Complex32> other, Matrix<Complex32> result)
         {
             // diagonal + diagonal = diagonal
-            var diagOther = other as DiagonalMatrix;
-            var diagResult = result as DiagonalMatrix;
-            if (diagOther != null && diagResult != null)
+            if (other is DiagonalMatrix diagOther && result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.AddArrays(_data, diagOther._data, diagResult._data);
                 return;
@@ -259,9 +255,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         protected override void DoSubtract(Matrix<Complex32> other, Matrix<Complex32> result)
         {
             // diagonal - diagonal = diagonal
-            var diagOther = other as DiagonalMatrix;
-            var diagResult = result as DiagonalMatrix;
-            if (diagOther != null && diagResult != null)
+            if (other is DiagonalMatrix diagOther && result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.SubtractArrays(_data, diagOther._data, diagResult._data);
                 return;
@@ -319,9 +313,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
 
             if (d == ColumnCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<Complex32>;
-                var denseResult = result.Storage as DenseVectorStorage<Complex32>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<Complex32> denseOther && result.Storage is DenseVectorStorage<Complex32> denseResult)
                 {
                     LinearAlgebraControl.Provider.PointWiseMultiplyArrays(_data, denseOther.Data, denseResult.Data);
                     return;
@@ -341,9 +333,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex32[diagonalResult._data.Length];
                 var otherDataCopy = new Complex32[diagonalResult._data.Length];
@@ -353,8 +343,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex32> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -394,9 +383,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeAndMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex32[diagonalResult._data.Length];
                 var otherDataCopy = new Complex32[diagonalResult._data.Length];
@@ -406,8 +393,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex32> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -438,9 +424,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeAndMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex32[diagonalResult._data.Length];
                 var otherDataCopy = new Complex32[diagonalResult._data.Length];
@@ -452,8 +436,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex32> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -484,9 +467,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex32[diagonalResult._data.Length];
                 var otherDataCopy = new Complex32[diagonalResult._data.Length];
@@ -496,8 +477,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex32> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -537,9 +517,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoConjugateTransposeThisAndMultiply(Matrix<Complex32> other, Matrix<Complex32> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new Complex32[diagonalResult._data.Length];
                 var otherDataCopy = new Complex32[diagonalResult._data.Length];
@@ -551,8 +529,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex32> denseOther)
             {
                 var dense = denseOther.Data;
                 var conjugateDiagonal = new Complex32[_data.Length];
@@ -597,9 +574,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
 
             if (d == RowCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<Complex32>;
-                var denseResult = result.Storage as DenseVectorStorage<Complex32>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<Complex32> denseOther && result.Storage is DenseVectorStorage<Complex32> denseResult)
                 {
                     LinearAlgebraControl.Provider.PointWiseMultiplyArrays(_data, denseOther.Data, denseResult.Data);
                     return;
@@ -627,9 +602,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
 
             if (d == RowCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<Complex32>;
-                var denseResult = result.Storage as DenseVectorStorage<Complex32>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<Complex32> denseOther && result.Storage is DenseVectorStorage<Complex32> denseResult)
                 {
                     // TODO: merge/MulByConj
                     LinearAlgebraControl.Provider.ConjugateArray(_data, denseResult.Data);
@@ -657,8 +630,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(1.0f/divisor, _data, diagResult._data);
                 return;
@@ -678,8 +650,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">The matrix to store the result of the division.</param>
         protected override void DoDivideByThis(Complex32 dividend, Matrix<Complex32> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 var resultData = diagResult._data;
                 CommonParallel.For(0, _data.Length, 4096, (a, b) =>

src/Numerics/LinearAlgebra/Complex32/Factorization/Svd.cs

@@ -74,13 +74,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Factorization
         /// Gets the two norm of the <see cref="Matrix{T}"/>.
         /// </summary>
         /// <returns>The 2-norm of the <see cref="Matrix{T}"/>.</returns>
-        public override double L2Norm
-        {
-            get
-            {
-                return S[0].Magnitude;
-            }
-        }
+        public override double L2Norm => S[0].Magnitude;
 
         /// <summary>
         /// Gets the condition number <b>max(S) / min(S)</b>

src/Numerics/LinearAlgebra/Complex32/Solvers/GpBiCg.cs

@@ -80,7 +80,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers
         /// </summary>
         public int NumberOfBiCgStabSteps
         {
-            get { return _numberOfBiCgStabSteps; }
+            get => _numberOfBiCgStabSteps;
 
             set
             {
@@ -99,7 +99,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers
         /// </summary>
         public int NumberOfGpBiCgSteps
         {
-            get { return _numberOfGpbiCgSteps; }
+            get => _numberOfGpbiCgSteps;
 
             set
             {

src/Numerics/LinearAlgebra/Complex32/Solvers/ILUTPPreconditioner.cs

@@ -162,7 +162,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double FillLevel
         {
-            get { return _fillLevel; }
+            get => _fillLevel;
             set
             {
                 if (value < 0)
@@ -193,7 +193,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double DropTolerance
         {
-            get { return _dropTolerance; }
+            get => _dropTolerance;
             set
             {
                 if (value < 0)
@@ -226,7 +226,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double PivotTolerance
         {
-            get { return _pivotTolerance; }
+            get => _pivotTolerance;
             set
             {
                 if (value < 0)

src/Numerics/LinearAlgebra/Complex32/Solvers/MlkBiCgStab.cs

@@ -87,7 +87,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers
         public int NumberOfStartingVectors
         {
             [DebuggerStepThrough]
-            get { return _numberOfStartingVectors; }
+            get => _numberOfStartingVectors;
 
             [DebuggerStepThrough]
             set
@@ -116,7 +116,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers
         public IList<Vector<Numerics.Complex32>> StartingVectors
         {
             [DebuggerStepThrough]
-            get { return _startingVectors; }
+            get => _startingVectors;
 
             [DebuggerStepThrough]
             set

src/Numerics/LinearAlgebra/Complex32/SparseMatrix.cs

@@ -53,10 +53,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// Gets the number of non zero elements in the matrix.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int NonZerosCount
-        {
-            get { return _storage.ValueCount; }
-        }
+        public int NonZerosCount => _storage.ValueCount;
 
         /// <summary>
         /// Create a new sparse matrix straight from an initialized matrix storage instance.
@@ -889,8 +886,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<Complex32>;
-            if (diagonalOther != null && sparseResult != null)
+            if (other.Storage is DiagonalMatrixStorage<Complex32> diagonalOther && sparseResult != null)
             {
                 var diagonal = diagonalOther.Data;
                 if (other.ColumnCount == other.RowCount)
@@ -911,8 +907,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
             var rowPointers = _storage.RowPointers;
             var columnIndices = _storage.ColumnIndices;
             var values = _storage.Values;
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<Complex32>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<Complex32> denseOther)
             {
                 // in this case we can directly address the underlying data-array
                 for (var row = 0; row < RowCount; row++)

src/Numerics/LinearAlgebra/Complex32/SparseVector.cs

@@ -52,10 +52,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// Gets the number of non zero elements in the vector.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int NonZerosCount
-        {
-            get { return _storage.ValueCount; }
-        }
+        public int NonZerosCount => _storage.ValueCount;
 
         /// <summary>
         /// Create a new sparse vector straight from an initialized vector storage instance.
@@ -404,8 +401,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <param name="result">Target vector</param>
         protected override void DoConjugate(Vector<Complex32> result)
         {
-            var sparseResult = result as SparseVector;
-            if (sparseResult != null)
+            if (result is SparseVector sparseResult)
             {
                 if (!ReferenceEquals(this, result))
                 {
@@ -931,7 +927,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
 
         public override string ToTypeString()
         {
-            return string.Format("SparseVector {0}-Complex32 {1:P2} Filled", Count, NonZerosCount / (double)Count);
+            return FormattableString.Invariant($"SparseVector {Count}-Complex32 {NonZerosCount / (double) Count:P2} Filled");
         }
     }
 }

src/Numerics/LinearAlgebra/Double/DenseMatrix.cs

@@ -393,10 +393,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// Gets the matrix's data.
         /// </summary>
         /// <value>The matrix's data.</value>
-        public double[] Values
-        {
-            get { return _values; }
-        }
+        public double[] Values => _values;
 
         /// <summary>Calculates the induced L1 norm of this matrix.</summary>
         /// <returns>The maximum absolute column sum of the matrix.</returns>
@@ -425,8 +422,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The result of the negation.</param>
         protected override void DoNegate(Matrix<double> result)
         {
-            var denseResult = result as DenseMatrix;
-            if (denseResult != null)
+            if (result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(-1, _values, denseResult._values);
                 return;
@@ -469,17 +465,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         protected override void DoAdd(Matrix<double> other, Matrix<double> result)
         {
             // dense + dense = dense
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<double>;
-            var denseResult = result.Storage as DenseColumnMajorMatrixStorage<double>;
-            if (denseOther != null && denseResult != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<double> denseOther && result.Storage is DenseColumnMajorMatrixStorage<double> denseResult)
             {
                 LinearAlgebraControl.Provider.AddArrays(_values, denseOther.Data, denseResult.Data);
                 return;
             }
 
             // dense + diagonal = any
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<double>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<double> diagonalOther)
             {
                 Storage.CopyToUnchecked(result.Storage, ExistingData.Clear);
                 var diagonal = diagonalOther.Data;
@@ -525,17 +518,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         protected override void DoSubtract(Matrix<double> other, Matrix<double> result)
         {
             // dense + dense = dense
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<double>;
-            var denseResult = result.Storage as DenseColumnMajorMatrixStorage<double>;
-            if (denseOther != null && denseResult != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<double> denseOther && result.Storage is DenseColumnMajorMatrixStorage<double> denseResult)
             {
                 LinearAlgebraControl.Provider.SubtractArrays(_values, denseOther.Data, denseResult.Data);
                 return;
             }
 
             // dense + diagonal = matrix
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<double>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<double> diagonalOther)
             {
                 CopyTo(result);
                 var diagonal = diagonalOther.Data;
@@ -601,9 +591,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<double> other, Matrix<double> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiply(
                     _values,
@@ -616,8 +604,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<double>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<double> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(ColumnCount, other.ColumnCount);
@@ -647,9 +634,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeAndMultiply(Matrix<double> other, Matrix<double> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.DontTranspose,
@@ -666,8 +651,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<double>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<double> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(ColumnCount, other.RowCount);
@@ -728,9 +712,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Matrix<double> other, Matrix<double> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.Transpose,
@@ -747,8 +729,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<double>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<double> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(RowCount, other.ColumnCount);

src/Numerics/LinearAlgebra/Double/DenseVector.cs

@@ -162,10 +162,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// Gets the vector's data.
         /// </summary>
         /// <value>The vector's data.</value>
-        public double[] Values
-        {
-            get { return _values; }
-        }
+        public double[] Values => _values;
 
         /// <summary>
         /// Returns a reference to the internal data structure.

src/Numerics/LinearAlgebra/Double/DiagonalMatrix.cs

@@ -190,8 +190,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The result of the negation.</param>
         protected override void DoNegate(Matrix<double> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(-1, _data, diagResult._data);
                 return;
@@ -213,9 +212,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         protected override void DoAdd(Matrix<double> other, Matrix<double> result)
         {
             // diagonal + diagonal = diagonal
-            var diagOther = other as DiagonalMatrix;
-            var diagResult = result as DiagonalMatrix;
-            if (diagOther != null && diagResult != null)
+            if (other is DiagonalMatrix diagOther && result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.AddArrays(_data, diagOther._data, diagResult._data);
                 return;
@@ -237,9 +234,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         protected override void DoSubtract(Matrix<double> other, Matrix<double> result)
         {
             // diagonal - diagonal = diagonal
-            var diagOther = other as DiagonalMatrix;
-            var diagResult = result as DiagonalMatrix;
-            if (diagOther != null && diagResult != null)
+            if (other is DiagonalMatrix diagOther && result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.SubtractArrays(_data, diagOther._data, diagResult._data);
                 return;
@@ -298,9 +293,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
 
             if (d == ColumnCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<double>;
-                var denseResult = result.Storage as DenseVectorStorage<double>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<double> denseOther && result.Storage is DenseVectorStorage<double> denseResult)
                 {
                     LinearAlgebraControl.Provider.PointWiseMultiplyArrays(_data, denseOther.Data, denseResult.Data);
                     return;
@@ -320,9 +313,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<double> other, Matrix<double> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new double[diagonalResult._data.Length];
                 var otherDataCopy = new double[diagonalResult._data.Length];
@@ -332,8 +323,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<double>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<double> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -373,9 +363,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeAndMultiply(Matrix<double> other, Matrix<double> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new double[diagonalResult._data.Length];
                 var otherDataCopy = new double[diagonalResult._data.Length];
@@ -385,8 +373,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<double>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<double> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -417,9 +404,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Matrix<double> other, Matrix<double> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new double[diagonalResult._data.Length];
                 var otherDataCopy = new double[diagonalResult._data.Length];
@@ -429,8 +414,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<double>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<double> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -478,9 +462,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
 
             if (d == RowCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<double>;
-                var denseResult = result.Storage as DenseVectorStorage<double>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<double> denseOther && result.Storage is DenseVectorStorage<double> denseResult)
                 {
                     LinearAlgebraControl.Provider.PointWiseMultiplyArrays(_data, denseOther.Data, denseResult.Data);
                     return;
@@ -506,8 +488,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return;
             }
 
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(1.0/divisor, _data, diagResult._data);
                 return;
@@ -527,8 +508,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <param name="result">The matrix to store the result of the division.</param>
         protected override void DoDivideByThis(double dividend, Matrix<double> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 var resultData = diagResult._data;
                 CommonParallel.For(0, _data.Length, 4096, (a, b) =>

src/Numerics/LinearAlgebra/Double/Factorization/Svd.cs

@@ -72,13 +72,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Factorization
         /// Gets the two norm of the <see cref="Matrix{T}"/>.
         /// </summary>
         /// <returns>The 2-norm of the <see cref="Matrix{T}"/>.</returns>
-        public override double L2Norm
-        {
-            get
-            {
-                return Math.Abs(S[0]);
-            }
-        }
+        public override double L2Norm => Math.Abs(S[0]);
 
         /// <summary>
         /// Gets the condition number <b>max(S) / min(S)</b>

src/Numerics/LinearAlgebra/Double/Solvers/GpBiCg.cs

@@ -80,10 +80,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers
         /// </summary>
         public int NumberOfBiCgStabSteps
         {
-            get
-            {
-                return _numberOfBiCgStabSteps;
-            }
+            get => _numberOfBiCgStabSteps;
 
             set
             {
@@ -102,10 +99,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers
         /// </summary>
         public int NumberOfGpBiCgSteps
         {
-            get
-            {
-                return _numberOfGpbiCgSteps;
-            }
+            get => _numberOfGpbiCgSteps;
 
             set
             {

src/Numerics/LinearAlgebra/Double/Solvers/ILUTPPreconditioner.cs

@@ -160,7 +160,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double FillLevel
         {
-            get { return _fillLevel; }
+            get => _fillLevel;
             set
             {
                 if (value < 0)
@@ -191,7 +191,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double DropTolerance
         {
-            get { return _dropTolerance; }
+            get => _dropTolerance;
             set
             {
                 if (value < 0)
@@ -224,7 +224,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double PivotTolerance
         {
-            get { return _pivotTolerance; }
+            get => _pivotTolerance;
             set
             {
                 if (value < 0)

src/Numerics/LinearAlgebra/Double/Solvers/MlkBiCgStab.cs

@@ -87,10 +87,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers
         public int NumberOfStartingVectors
         {
             [DebuggerStepThrough]
-            get
-            {
-                return _numberOfStartingVectors;
-            }
+            get => _numberOfStartingVectors;
 
             [DebuggerStepThrough]
             set
@@ -119,10 +116,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers
         public IList<Vector<double>> StartingVectors
         {
             [DebuggerStepThrough]
-            get
-            {
-                return _startingVectors;
-            }
+            get => _startingVectors;
 
             [DebuggerStepThrough]
             set

src/Numerics/LinearAlgebra/Double/SparseMatrix.cs

@@ -51,10 +51,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// Gets the number of non zero elements in the matrix.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int NonZerosCount
-        {
-            get { return _storage.ValueCount; }
-        }
+        public int NonZerosCount => _storage.ValueCount;
 
         /// <summary>
         /// Create a new sparse matrix straight from an initialized matrix storage instance.
@@ -890,8 +887,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<double>;
-            if (diagonalOther != null && sparseResult != null)
+            if (other.Storage is DiagonalMatrixStorage<double> diagonalOther && sparseResult != null)
             {
                 var diagonal = diagonalOther.Data;
                 if (other.ColumnCount == other.RowCount)
@@ -911,8 +907,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             var columnIndices = _storage.ColumnIndices;
             var values = _storage.Values;
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<double>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<double> denseOther)
             {
                 // in this case we can directly address the underlying data-array
                 for (var row = 0; row < RowCount; row++)
@@ -1561,7 +1556,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
 
         public override string ToTypeString()
         {
-            return string.Format("SparseMatrix {0}x{1}-Double {2:P2} Filled", RowCount, ColumnCount, NonZerosCount / (RowCount * (double)ColumnCount));
+            return FormattableString.Invariant($"SparseMatrix {RowCount}x{ColumnCount}-Double {NonZerosCount / (RowCount * (double) ColumnCount):P2} Filled");
         }
     }
 }

src/Numerics/LinearAlgebra/Double/SparseVector.cs

@@ -52,10 +52,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// Gets the number of non zero elements in the vector.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int NonZerosCount
-        {
-            get { return _storage.ValueCount; }
-        }
+        public int NonZerosCount => _storage.ValueCount;
 
         /// <summary>
         /// Create a new sparse vector straight from an initialized vector storage instance.
@@ -952,7 +949,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
 
         public override string ToTypeString()
         {
-            return string.Format("SparseVector {0}-Double {1:P2} Filled", Count, NonZerosCount / (double)Count);
+            return FormattableString.Invariant($"SparseVector {Count}-Double {NonZerosCount / (double) Count:P2} Filled");
         }
     }
 }

src/Numerics/LinearAlgebra/Factorization/LU.cs

@@ -77,26 +77,17 @@ namespace MathNet.Numerics.LinearAlgebra.Factorization
         /// <summary>
         /// Gets the lower triangular factor.
         /// </summary>
-        public Matrix<T> L
-        {
-            get { return _lazyL.Value; }
-        }
+        public Matrix<T> L => _lazyL.Value;
 
         /// <summary>
         /// Gets the upper triangular factor.
         /// </summary>
-        public Matrix<T> U
-        {
-            get { return _lazyU.Value; }
-        }
+        public Matrix<T> U => _lazyU.Value;
 
         /// <summary>
         /// Gets the permutation applied to LU factorization.
         /// </summary>
-        public Permutation P
-        {
-            get { return _lazyP.Value; }
-        }
+        public Permutation P => _lazyP.Value;
 
         /// <summary>
         /// Gets the determinant of the matrix for which the LU factorization was computed.

src/Numerics/LinearAlgebra/Factorization/QR.cs

@@ -80,15 +80,12 @@ namespace MathNet.Numerics.LinearAlgebra.Factorization
         /// <summary>
         /// Gets or sets orthogonal Q matrix
         /// </summary>
-        public Matrix<T> Q { get; private set; }
+        public Matrix<T> Q { get; }
 
         /// <summary>
         /// Gets the upper triangular factor R.
         /// </summary>
-        public Matrix<T> R
-        {
-            get { return _lazyR.Value; }
-        }
+        public Matrix<T> R => _lazyR.Value;
 
         /// <summary>
         /// Gets the absolute determinant value of the matrix for which the QR matrix was computed.

src/Numerics/LinearAlgebra/Factorization/Svd.cs

@@ -88,26 +88,23 @@ namespace MathNet.Numerics.LinearAlgebra.Factorization
         /// <summary>
         /// Gets the singular values (Σ) of matrix in ascending value.
         /// </summary>
-        public Vector<T> S { get; private set; }
+        public Vector<T> S { get; }
 
         /// <summary>
         /// Gets the left singular vectors (U - m-by-m unitary matrix)
         /// </summary>
-        public Matrix<T> U { get; private set; }
+        public Matrix<T> U { get; }
 
         /// <summary>
         /// Gets the transpose right singular vectors (transpose of V, an n-by-n unitary matrix)
         /// </summary>
-        public Matrix<T> VT { get; private set; }
+        public Matrix<T> VT { get; }
 
         /// <summary>
         /// Returns the singular values as a diagonal <see cref="Matrix{T}"/>.
         /// </summary>
         /// <returns>The singular values as a diagonal <see cref="Matrix{T}"/>.</returns>
-        public Matrix<T> W
-        {
-            get { return _lazyW.Value; }
-        }
+        public Matrix<T> W => _lazyW.Value;
 
         /// <summary>
         /// Gets the effective numerical matrix rank.

src/Numerics/LinearAlgebra/Matrix.BCL.cs

@@ -62,8 +62,7 @@ namespace MathNet.Numerics.LinearAlgebra
         /// </returns>
         public override bool Equals(object obj)
         {
-            var other = obj as Matrix<T>;
-            return other != null && Storage.Equals(other.Storage);
+            return obj is Matrix<T> other && Storage.Equals(other.Storage);
         }
 
         /// <summary>
@@ -97,7 +96,7 @@ namespace MathNet.Numerics.LinearAlgebra
         /// </summary>
         public virtual string ToTypeString()
         {
-            return string.Format("{0} {1}x{2}-{3}", GetType().Name, RowCount, ColumnCount, typeof (T).Name);
+            return FormattableString.Invariant($"{GetType().Name} {RowCount}x{ColumnCount}-{typeof(T).Name}");
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Single/DenseMatrix.cs

@@ -393,10 +393,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// Gets the matrix's data.
         /// </summary>
         /// <value>The matrix's data.</value>
-        public float[] Values
-        {
-            get { return _values; }
-        }
+        public float[] Values => _values;
 
         /// <summary>Calculates the induced L1 norm of this matrix.</summary>
         /// <returns>The maximum absolute column sum of the matrix.</returns>
@@ -425,8 +422,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the negation.</param>
         protected override void DoNegate(Matrix<float> result)
         {
-            var denseResult = result as DenseMatrix;
-            if (denseResult != null)
+            if (result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(-1, _values, denseResult._values);
                 return;
@@ -469,17 +465,14 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         protected override void DoAdd(Matrix<float> other, Matrix<float> result)
         {
             // dense + dense = dense
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<float>;
-            var denseResult = result.Storage as DenseColumnMajorMatrixStorage<float>;
-            if (denseOther != null && denseResult != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<float> denseOther && result.Storage is DenseColumnMajorMatrixStorage<float> denseResult)
             {
                 LinearAlgebraControl.Provider.AddArrays(_values, denseOther.Data, denseResult.Data);
                 return;
             }
 
             // dense + diagonal = any
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<float>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<float> diagonalOther)
             {
                 Storage.CopyToUnchecked(result.Storage, ExistingData.Clear);
                 var diagonal = diagonalOther.Data;
@@ -525,17 +518,14 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         protected override void DoSubtract(Matrix<float> other, Matrix<float> result)
         {
             // dense + dense = dense
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<float>;
-            var denseResult = result.Storage as DenseColumnMajorMatrixStorage<float>;
-            if (denseOther != null && denseResult != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<float> denseOther && result.Storage is DenseColumnMajorMatrixStorage<float> denseResult)
             {
                 LinearAlgebraControl.Provider.SubtractArrays(_values, denseOther.Data, denseResult.Data);
                 return;
             }
 
             // dense + diagonal = matrix
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<float>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<float> diagonalOther)
             {
                 CopyTo(result);
                 var diagonal = diagonalOther.Data;
@@ -601,9 +591,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<float> other, Matrix<float> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiply(
                     _values,
@@ -616,8 +604,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<float>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<float> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(ColumnCount, other.ColumnCount);
@@ -647,9 +634,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeAndMultiply(Matrix<float> other, Matrix<float> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.DontTranspose,
@@ -666,8 +651,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<float>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<float> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(ColumnCount, other.RowCount);
@@ -697,14 +681,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Vector<float> rightSide, Vector<float> result)
         {
-            var denseRight = rightSide as DenseVector;
-            var denseResult = result as DenseVector;
-
-            if (denseRight == null || denseResult == null)
-            {
-                base.DoTransposeThisAndMultiply(rightSide, result);
-            }
-            else
+            if (rightSide is DenseVector denseRight && result is DenseVector denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.Transpose,
@@ -719,6 +696,10 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                     0.0f,
                     denseResult.Values);
             }
+            else
+            {
+                base.DoTransposeThisAndMultiply(rightSide, result);
+            }
         }
 
         /// <summary>
@@ -728,9 +709,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Matrix<float> other, Matrix<float> result)
         {
-            var denseOther = other as DenseMatrix;
-            var denseResult = result as DenseMatrix;
-            if (denseOther != null && denseResult != null)
+            if (other is DenseMatrix denseOther && result is DenseMatrix denseResult)
             {
                 LinearAlgebraControl.Provider.MatrixMultiplyWithUpdate(
                     Providers.LinearAlgebra.Transpose.Transpose,
@@ -747,8 +726,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<float>;
-            if (diagonalOther != null)
+            if (other.Storage is DiagonalMatrixStorage<float> diagonalOther)
             {
                 var diagonal = diagonalOther.Data;
                 var d = Math.Min(RowCount, other.ColumnCount);

src/Numerics/LinearAlgebra/Single/DenseVector.cs

@@ -162,10 +162,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// Gets the vector's data.
         /// </summary>
         /// <value>The vector's data.</value>
-        public float[] Values
-        {
-            get { return _values; }
-        }
+        public float[] Values => _values;
 
         /// <summary>
         /// Returns a reference to the internal data structure.

src/Numerics/LinearAlgebra/Single/DiagonalMatrix.cs

@@ -190,8 +190,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the negation.</param>
         protected override void DoNegate(Matrix<float> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(-1, _data, diagResult._data);
                 return;
@@ -213,9 +212,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         protected override void DoAdd(Matrix<float> other, Matrix<float> result)
         {
             // diagonal + diagonal = diagonal
-            var diagOther = other as DiagonalMatrix;
-            var diagResult = result as DiagonalMatrix;
-            if (diagOther != null && diagResult != null)
+            if (other is DiagonalMatrix diagOther && result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.AddArrays(_data, diagOther._data, diagResult._data);
                 return;
@@ -237,9 +234,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         protected override void DoSubtract(Matrix<float> other, Matrix<float> result)
         {
             // diagonal - diagonal = diagonal
-            var diagOther = other as DiagonalMatrix;
-            var diagResult = result as DiagonalMatrix;
-            if (diagOther != null && diagResult != null)
+            if (other is DiagonalMatrix diagOther && result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.SubtractArrays(_data, diagOther._data, diagResult._data);
                 return;
@@ -298,9 +293,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
 
             if (d == ColumnCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<float>;
-                var denseResult = result.Storage as DenseVectorStorage<float>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<float> denseOther && result.Storage is DenseVectorStorage<float> denseResult)
                 {
                     LinearAlgebraControl.Provider.PointWiseMultiplyArrays(_data, denseOther.Data, denseResult.Data);
                     return;
@@ -320,9 +313,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<float> other, Matrix<float> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new float[diagonalResult._data.Length];
                 var otherDataCopy = new float[diagonalResult._data.Length];
@@ -332,8 +323,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<float>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<float> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -373,9 +363,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeAndMultiply(Matrix<float> other, Matrix<float> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new float[diagonalResult._data.Length];
                 var otherDataCopy = new float[diagonalResult._data.Length];
@@ -385,8 +373,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<float>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<float> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -417,9 +404,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoTransposeThisAndMultiply(Matrix<float> other, Matrix<float> result)
         {
-            var diagonalOther = other as DiagonalMatrix;
-            var diagonalResult = result as DiagonalMatrix;
-            if (diagonalOther != null && diagonalResult != null)
+            if (other is DiagonalMatrix diagonalOther && result is DiagonalMatrix diagonalResult)
             {
                 var thisDataCopy = new float[diagonalResult._data.Length];
                 var otherDataCopy = new float[diagonalResult._data.Length];
@@ -429,8 +414,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return;
             }
 
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<float>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<float> denseOther)
             {
                 var dense = denseOther.Data;
                 var diagonal = _data;
@@ -478,9 +462,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
 
             if (d == RowCount)
             {
-                var denseOther = rightSide.Storage as DenseVectorStorage<float>;
-                var denseResult = result.Storage as DenseVectorStorage<float>;
-                if (denseOther != null && denseResult != null)
+                if (rightSide.Storage is DenseVectorStorage<float> denseOther && result.Storage is DenseVectorStorage<float> denseResult)
                 {
                     LinearAlgebraControl.Provider.PointWiseMultiplyArrays(_data, denseOther.Data, denseResult.Data);
                     return;
@@ -506,8 +488,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return;
             }
 
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 LinearAlgebraControl.Provider.ScaleArray(1.0f/divisor, _data, diagResult._data);
                 return;
@@ -527,8 +508,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The matrix to store the result of the division.</param>
         protected override void DoDivideByThis(float dividend, Matrix<float> result)
         {
-            var diagResult = result as DiagonalMatrix;
-            if (diagResult != null)
+            if (result is DiagonalMatrix diagResult)
             {
                 var resultData = diagResult._data;
                 CommonParallel.For(0, _data.Length, 4096, (a, b) =>

src/Numerics/LinearAlgebra/Single/Factorization/Svd.cs

@@ -72,13 +72,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Factorization
         /// Gets the two norm of the <see cref="Matrix{T}"/>.
         /// </summary>
         /// <returns>The 2-norm of the <see cref="Matrix{T}"/>.</returns>
-        public override double L2Norm
-        {
-            get
-            {
-                return Math.Abs(S[0]);
-            }
-        }
+        public override double L2Norm => Math.Abs(S[0]);
 
         /// <summary>
         /// Gets the condition number <b>max(S) / min(S)</b>

src/Numerics/LinearAlgebra/Single/Solvers/GpBiCg.cs

@@ -80,7 +80,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers
         /// </summary>
         public int NumberOfBiCgStabSteps
         {
-            get { return _numberOfBiCgStabSteps; }
+            get => _numberOfBiCgStabSteps;
 
             set
             {
@@ -99,7 +99,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers
         /// </summary>
         public int NumberOfGpBiCgSteps
         {
-            get { return _numberOfGpbiCgSteps; }
+            get => _numberOfGpbiCgSteps;
 
             set
             {

src/Numerics/LinearAlgebra/Single/Solvers/ILUTPPreconditioner.cs

@@ -160,7 +160,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double FillLevel
         {
-            get { return _fillLevel; }
+            get => _fillLevel;
             set
             {
                 if (value < 0)
@@ -191,7 +191,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double DropTolerance
         {
-            get { return _dropTolerance; }
+            get => _dropTolerance;
             set
             {
                 if (value < 0)
@@ -224,7 +224,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers
         /// <exception cref="ArgumentOutOfRangeException">Thrown if a negative value is provided.</exception>
         public double PivotTolerance
         {
-            get { return _pivotTolerance; }
+            get => _pivotTolerance;
             set
             {
                 if (value < 0)

src/Numerics/LinearAlgebra/Single/Solvers/MlkBiCgStab.cs

@@ -86,10 +86,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers
         public int NumberOfStartingVectors
         {
             [DebuggerStepThrough]
-            get
-            {
-                return _numberOfStartingVectors;
-            }
+            get => _numberOfStartingVectors;
 
             [DebuggerStepThrough]
             set
@@ -118,10 +115,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers
         public IList<Vector<float>> StartingVectors
         {
             [DebuggerStepThrough]
-            get
-            {
-                return _startingVectors;
-            }
+            get => _startingVectors;
 
             [DebuggerStepThrough]
             set

src/Numerics/LinearAlgebra/Single/SparseMatrix.cs

@@ -52,10 +52,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// Gets the number of non zero elements in the matrix.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int NonZerosCount
-        {
-            get { return _storage.ValueCount; }
-        }
+        public int NonZerosCount => _storage.ValueCount;
 
         /// <summary>
         /// Create a new sparse matrix straight from an initialized matrix storage instance.
@@ -894,8 +891,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return;
             }
 
-            var diagonalOther = other.Storage as DiagonalMatrixStorage<float>;
-            if (diagonalOther != null && sparseResult != null)
+            if (other.Storage is DiagonalMatrixStorage<float> diagonalOther && sparseResult != null)
             {
                 var diagonal = diagonalOther.Data;
                 if (other.ColumnCount == other.RowCount)
@@ -914,8 +910,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
             var rowPointers = _storage.RowPointers;
             var columnIndices = _storage.ColumnIndices;
             var values = _storage.Values;
-            var denseOther = other.Storage as DenseColumnMajorMatrixStorage<float>;
-            if (denseOther != null)
+            if (other.Storage is DenseColumnMajorMatrixStorage<float> denseOther)
             {
                 // in this case we can directly address the underlying data-array
                 for (var row = 0; row < RowCount; row++)
@@ -1568,7 +1563,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
 
         public override string ToTypeString()
         {
-            return string.Format("SparseMatrix {0}x{1}-Single {2:P2} Filled", RowCount, ColumnCount, NonZerosCount / (RowCount * (double)ColumnCount));
+            return FormattableString.Invariant($"SparseMatrix {RowCount}x{ColumnCount}-Single {NonZerosCount / (RowCount * (double) ColumnCount):P2} Filled");
         }
     }
 }

src/Numerics/LinearAlgebra/Single/SparseVector.cs

@@ -52,10 +52,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// Gets the number of non zero elements in the vector.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int NonZerosCount
-        {
-            get { return _storage.ValueCount; }
-        }
+        public int NonZerosCount => _storage.ValueCount;
 
         /// <summary>
         /// Create a new sparse vector straight from an initialized vector storage instance.
@@ -953,7 +950,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
 
         public override string ToTypeString()
         {
-            return string.Format("SparseVector {0}-Single {1:P2} Filled", Count, NonZerosCount / (double)Count);
+            return FormattableString.Invariant($"SparseVector {Count}-Single {NonZerosCount / (double) Count:P2} Filled");
         }
     }
 }

src/Numerics/LinearAlgebra/Solvers/CancellationStopCriterion.cs

@@ -83,7 +83,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public IterationStatus Status
         {
             [DebuggerStepThrough]
-            get { return _currentTcs.Token.IsCancellationRequested ? IterationStatus.Cancelled : IterationStatus.Continue; }
+            get => _currentTcs.Token.IsCancellationRequested ? IterationStatus.Cancelled : IterationStatus.Continue;
         }
 
         public void Cancel()

src/Numerics/LinearAlgebra/Solvers/DelegateStopCriterion.cs

@@ -70,10 +70,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         /// <summary>
         /// Gets the current calculation status.
         /// </summary>
-        public IterationStatus Status
-        {
-            get { return _status; }
-        }
+        public IterationStatus Status => _status;
 
         /// <summary>
         /// Resets the IIterationStopCriterion to the pre-calculation state.

src/Numerics/LinearAlgebra/Solvers/DivergenceStopCriterion.cs

@@ -92,7 +92,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public double MaximumRelativeIncrease
         {
             [DebuggerStepThrough]
-            get { return _maximumRelativeIncrease; }
+            get => _maximumRelativeIncrease;
 
             [DebuggerStepThrough]
             set
@@ -114,7 +114,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public int MinimumNumberOfIterations
         {
             [DebuggerStepThrough]
-            get { return _minimumNumberOfIterations; }
+            get => _minimumNumberOfIterations;
 
             [DebuggerStepThrough]
             set
@@ -220,7 +220,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         int RequiredHistoryLength
         {
             [DebuggerStepThrough]
-            get { return _minimumNumberOfIterations + 1; }
+            get => _minimumNumberOfIterations + 1;
         }
 
         /// <summary>
@@ -229,7 +229,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public IterationStatus Status
         {
             [DebuggerStepThrough]
-            get { return _status; }
+            get => _status;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Solvers/FailureStopCriterion.cs

@@ -96,7 +96,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public IterationStatus Status
         {
             [DebuggerStepThrough]
-            get { return _status; }
+            get => _status;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Solvers/IterationCountStopCriterion.cs

@@ -84,7 +84,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public int MaximumNumberOfIterations
         {
             [DebuggerStepThrough]
-            get { return _maximumNumberOfIterations; }
+            get => _maximumNumberOfIterations;
 
             [DebuggerStepThrough]
             set
@@ -137,7 +137,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public IterationStatus Status
         {
             [DebuggerStepThrough]
-            get { return _status; }
+            get => _status;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Solvers/Iterator.cs

@@ -85,10 +85,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         /// <summary>
         /// Gets the current calculation status.
         /// </summary>
-        public IterationStatus Status
-        {
-            get { return _status; }
-        }
+        public IterationStatus Status => _status;
 
         /// <summary>
         /// Determines the status of the iterative calculation based on the stop criteria stored

src/Numerics/LinearAlgebra/Solvers/ResidualStopCriterion.cs

@@ -99,7 +99,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public double Maximum
         {
             [DebuggerStepThrough]
-            get { return _maximum; }
+            get => _maximum;
 
             [DebuggerStepThrough]
             set
@@ -121,7 +121,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public int MinimumIterationsBelowMaximum
         {
             [DebuggerStepThrough]
-            get { return _minimumIterationsBelowMaximum; }
+            get => _minimumIterationsBelowMaximum;
 
             [DebuggerStepThrough]
             set
@@ -220,7 +220,7 @@ namespace MathNet.Numerics.LinearAlgebra.Solvers
         public IterationStatus Status
         {
             [DebuggerStepThrough]
-            get { return _status; }
+            get => _status;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Storage/DenseColumnMajorMatrixStorage.cs

@@ -71,19 +71,13 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         /// <summary>
         /// True if the matrix storage format is dense.
         /// </summary>
-        public override bool IsDense
-        {
-            get { return true; }
-        }
+        public override bool IsDense => true;
 
         /// <summary>
         /// True if all fields of this matrix can be set to any value.
         /// False if some fields are fixed, like on a diagonal matrix.
         /// </summary>
-        public override bool IsFullyMutable
-        {
-            get { return true; }
-        }
+        public override bool IsFullyMutable => true;
 
         /// <summary>
         /// True if the specified field can be set to any value.
@@ -300,8 +294,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             for (int j = 0; j < data.Length; j++)
             {
                 var column = data[j];
-                var denseColumn = column as DenseVectorStorage<T>;
-                if (denseColumn != null)
+                if (column is DenseVectorStorage<T> denseColumn)
                 {
                     Array.Copy(denseColumn.Data, 0, array, j*rows, rows);
                 }
@@ -351,8 +344,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         public static DenseColumnMajorMatrixStorage<T> OfColumnMajorEnumerable(int rows, int columns, IEnumerable<T> data)
         {
-            var arrayData = data as T[];
-            if (arrayData != null)
+            if (data is T[] arrayData)
             {
                 return OfColumnMajorArray(rows, columns, arrayData);
             }
@@ -373,8 +365,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 for (int column = 0; column < columns; column++)
                 {
                     if (!columnIterator.MoveNext()) throw new ArgumentOutOfRangeException(nameof(data), string.Format(Resources.ArgumentArrayWrongLength, columns));
-                    var arrayColumn = columnIterator.Current as T[];
-                    if (arrayColumn != null)
+                    if (columnIterator.Current is T[] arrayColumn)
                     {
                         Array.Copy(arrayColumn, 0, array, column*rows, rows);
                     }
@@ -424,8 +415,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 CopyToUnchecked(denseTarget);
                 return;
@@ -453,8 +443,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
             ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 CopySubMatrixToUnchecked(denseTarget, sourceRowIndex, targetRowIndex, rowCount, sourceColumnIndex, targetColumnIndex, columnCount);
                 return;
@@ -490,8 +479,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopySubRowToUnchecked(VectorStorage<T> target, int rowIndex, int sourceColumnIndex, int targetColumnIndex, int columnCount,
             ExistingData existingData)
         {
-            var targetDense = target as DenseVectorStorage<T>;
-            if (targetDense != null)
+            if (target is DenseVectorStorage<T> targetDense)
             {
                 for (int j = 0; j < columnCount; j++)
                 {
@@ -513,8 +501,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopySubColumnToUnchecked(VectorStorage<T> target, int columnIndex, int sourceRowIndex, int targetRowIndex, int rowCount,
             ExistingData existingData)
         {
-            var targetDense = target as DenseVectorStorage<T>;
-            if (targetDense != null)
+            if (target is DenseVectorStorage<T> targetDense)
             {
                 Array.Copy(Data, columnIndex*RowCount + sourceRowIndex, targetDense.Data, targetRowIndex, rowCount);
                 return;
@@ -533,15 +520,13 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 TransposeToUnchecked(denseTarget);
                 return;
             }
 
-            var sparseTarget = target as SparseCompressedRowMatrixStorage<T>;
-            if (sparseTarget != null)
+            if (target is SparseCompressedRowMatrixStorage<T> sparseTarget)
             {
                 TransposeToUnchecked(sparseTarget);
                 return;
@@ -743,8 +728,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override Tuple<int, int, T, TOther> Find2Unchecked<TOther>(MatrixStorage<TOther> other, Func<T, TOther, bool> predicate, Zeros zeros)
         {
-            var denseOther = other as DenseColumnMajorMatrixStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseColumnMajorMatrixStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
                 for (int i = 0; i < Data.Length; i++)
@@ -760,8 +744,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return null;
             }
 
-            var diagonalOther = other as DiagonalMatrixStorage<TOther>;
-            if (diagonalOther != null)
+            if (other is DiagonalMatrixStorage<TOther> diagonalOther)
             {
                 TOther[] otherData = diagonalOther.Data;
                 TOther otherZero = BuilderInstance<TOther>.Matrix.Zero;
@@ -780,8 +763,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return null;
             }
 
-            var sparseOther = other as SparseCompressedRowMatrixStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseCompressedRowMatrixStorage<TOther> sparseOther)
             {
                 int[] otherRowPointers = sparseOther.RowPointers;
                 int[] otherColumnIndices = sparseOther.ColumnIndices;
@@ -849,8 +831,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void MapToUnchecked<TU>(MatrixStorage<TU> target, Func<T, TU> f,
             Zeros zeros, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<TU>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<TU> denseTarget)
             {
                 CommonParallel.For(0, Data.Length, 4096, (a, b) =>
                 {
@@ -877,8 +858,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void MapIndexedToUnchecked<TU>(MatrixStorage<TU> target, Func<int, int, T, TU> f,
             Zeros zeros, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<TU>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<TU> denseTarget)
             {
                 CommonParallel.For(0, ColumnCount, Math.Max(4096/RowCount, 32), (a, b) =>
                 {
@@ -912,8 +892,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
             Zeros zeros, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<TU>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<TU> denseTarget)
             {
                 CommonParallel.For(0, columnCount, Math.Max(4096/rowCount, 32), (a, b) =>
                 {
@@ -975,8 +954,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override TState Fold2Unchecked<TOther, TState>(MatrixStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros)
         {
-            var denseOther = other as DenseColumnMajorMatrixStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseColumnMajorMatrixStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
                 for (int i = 0; i < Data.Length; i++)
@@ -986,8 +964,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return state;
             }
 
-            var diagonalOther = other as DiagonalMatrixStorage<TOther>;
-            if (diagonalOther != null)
+            if (other is DiagonalMatrixStorage<TOther> diagonalOther)
             {
                 TOther[] otherData = diagonalOther.Data;
                 TOther otherZero = BuilderInstance<TOther>.Matrix.Zero;
@@ -1003,8 +980,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return state;
             }
 
-            var sparseOther = other as SparseCompressedRowMatrixStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseCompressedRowMatrixStorage<TOther> sparseOther)
             {
                 int[] otherRowPointers = sparseOther.RowPointers;
                 int[] otherColumnIndices = sparseOther.ColumnIndices;

src/Numerics/LinearAlgebra/Storage/DenseVectorStorage.cs

@@ -71,10 +71,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         /// <summary>
         /// True if the vector storage format is dense.
         /// </summary>
-        public override bool IsDense
-        {
-            get { return true; }
-        }
+        public override bool IsDense => true;
 
         /// <summary>
         /// Retrieves the requested element without range checking.
@@ -156,8 +153,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 throw new ArgumentNullException(nameof(data));
             }
 
-            var arrayData = data as T[];
-            if (arrayData != null)
+            if (data is T[] arrayData)
             {
                 var copy = new T[arrayData.Length];
                 Array.Copy(arrayData, 0, copy, 0, arrayData.Length);
@@ -187,8 +183,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void CopyToUnchecked(VectorStorage<T> target, ExistingData existingData)
         {
-            var denseTarget = target as DenseVectorStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseVectorStorage<T> denseTarget)
             {
                 if (!ReferenceEquals(this, denseTarget))
                 {
@@ -198,8 +193,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return;
             }
 
-            var sparseTarget = target as SparseVectorStorage<T>;
-            if (sparseTarget != null)
+            if (target is SparseVectorStorage<T> sparseTarget)
             {
                 var indices = new List<int>();
                 var values = new List<T>();
@@ -232,8 +226,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void CopyToRowUnchecked(MatrixStorage<T> target, int rowIndex, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 for (int j = 0; j < Data.Length; j++)
                 {
@@ -254,8 +247,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void CopyToColumnUnchecked(MatrixStorage<T> target, int columnIndex, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 Array.Copy(Data, 0, denseTarget.Data, columnIndex*denseTarget.RowCount, Data.Length);
                 return;
@@ -274,8 +266,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopySubVectorToUnchecked(VectorStorage<T> target,
             int sourceIndex, int targetIndex, int count, ExistingData existingData)
         {
-            var denseTarget = target as DenseVectorStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseVectorStorage<T> denseTarget)
             {
                 Array.Copy(Data, sourceIndex, denseTarget.Data, targetIndex, count);
                 return;
@@ -291,8 +282,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopyToSubRowUnchecked(MatrixStorage<T> target, int rowIndex,
             int sourceColumnIndex, int targetColumnIndex, int columnCount, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 for (int j = 0; j < Data.Length; j++)
                 {
@@ -314,8 +304,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopyToSubColumnUnchecked(MatrixStorage<T> target, int columnIndex,
             int sourceRowIndex, int targetRowIndex, int rowCount, ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 Array.Copy(Data, sourceRowIndex, denseTarget.Data, columnIndex*denseTarget.RowCount + targetRowIndex, rowCount);
                 return;
@@ -387,8 +376,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override Tuple<int, T, TOther> Find2Unchecked<TOther>(VectorStorage<TOther> other, Func<T, TOther, bool> predicate, Zeros zeros)
         {
-            var denseOther = other as DenseVectorStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseVectorStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
                 for (int i = 0; i < Data.Length; i++)
@@ -402,8 +390,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return null;
             }
 
-            var sparseOther = other as SparseVectorStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseVectorStorage<TOther> sparseOther)
             {
                 int[] otherIndices = sparseOther.Indices;
                 TOther[] otherValues = sparseOther.Values;
@@ -462,8 +449,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void MapToUnchecked<TU>(VectorStorage<TU> target, Func<T, TU> f, Zeros zeros, ExistingData existingData)
         {
-            var denseTarget = target as DenseVectorStorage<TU>;
-            if (denseTarget != null)
+            if (target is DenseVectorStorage<TU> denseTarget)
             {
                 CommonParallel.For(0, Data.Length, 4096, (a, b) =>
                 {
@@ -485,8 +471,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void MapIndexedToUnchecked<TU>(VectorStorage<TU> target, Func<int, T, TU> f, Zeros zeros, ExistingData existingData)
         {
-            var denseTarget = target as DenseVectorStorage<TU>;
-            if (denseTarget != null)
+            if (target is DenseVectorStorage<TU> denseTarget)
             {
                 CommonParallel.For(0, Data.Length, 4096, (a, b) =>
                 {
@@ -519,8 +504,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             }
 
             var denseTarget = target as DenseVectorStorage<T>;
-            var denseOther = other as DenseVectorStorage<T>;
-            if (denseTarget != null && denseOther != null)
+            if (denseTarget != null && other is DenseVectorStorage<T> denseOther)
             {
                 CommonParallel.For(0, Data.Length, 4096, (a, b) =>
                 {
@@ -533,8 +517,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return;
             }
 
-            var sparseOther = other as SparseVectorStorage<T>;
-            if (denseTarget != null && sparseOther != null)
+            if (denseTarget != null && other is SparseVectorStorage<T> sparseOther)
             {
                 T[] targetData = denseTarget.Data;
                 int[] otherIndices = sparseOther.Indices;
@@ -565,8 +548,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override TState Fold2Unchecked<TOther, TState>(VectorStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros)
         {
-            var denseOther = other as DenseVectorStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseVectorStorage<TOther> denseOther)
             {
                 var otherData = denseOther.Data;
                 for (int i = 0; i < Data.Length; i++)
@@ -577,8 +559,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return state;
             }
 
-            var sparseOther = other as SparseVectorStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseVectorStorage<TOther> sparseOther)
             {
                 int[] otherIndices = sparseOther.Indices;
                 TOther[] otherValues = sparseOther.Values;

src/Numerics/LinearAlgebra/Storage/DiagonalMatrixStorage.cs

@@ -71,19 +71,13 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         /// <summary>
         /// True if the matrix storage format is dense.
         /// </summary>
-        public override bool IsDense
-        {
-            get { return false; }
-        }
+        public override bool IsDense => false;
 
         /// <summary>
         /// True if all fields of this matrix can be set to any value.
         /// False if some fields are fixed, like on a diagonal matrix.
         /// </summary>
-        public override bool IsFullyMutable
-        {
-            get { return false; }
-        }
+        public override bool IsFullyMutable => false;
 
         /// <summary>
         /// True if the specified field can be set to any value.
@@ -226,8 +220,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 throw new ArgumentNullException(nameof(data));
             }
 
-            var arrayData = data as T[];
-            if (arrayData != null)
+            if (data is T[] arrayData)
             {
                 var copy = new T[arrayData.Length];
                 Array.Copy(arrayData, 0, copy, 0, arrayData.Length);
@@ -256,22 +249,19 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
-            var diagonalTarget = target as DiagonalMatrixStorage<T>;
-            if (diagonalTarget != null)
+            if (target is DiagonalMatrixStorage<T> diagonalTarget)
             {
                 CopyToUnchecked(diagonalTarget);
                 return;
             }
 
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 CopyToUnchecked(denseTarget, existingData);
                 return;
             }
 
-            var sparseTarget = target as SparseCompressedRowMatrixStorage<T>;
-            if (sparseTarget != null)
+            if (target is SparseCompressedRowMatrixStorage<T> sparseTarget)
             {
                 CopyToUnchecked(sparseTarget, existingData);
                 return;
@@ -327,15 +317,13 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
             ExistingData existingData)
         {
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 CopySubMatrixToUnchecked(denseTarget, sourceRowIndex, targetRowIndex, rowCount, sourceColumnIndex, targetColumnIndex, columnCount, existingData);
                 return;
             }
 
-            var diagonalTarget = target as DiagonalMatrixStorage<T>;
-            if (diagonalTarget != null)
+            if (target is DiagonalMatrixStorage<T> diagonalTarget)
             {
                 CopySubMatrixToUnchecked(diagonalTarget, sourceRowIndex, targetRowIndex, rowCount, sourceColumnIndex, targetColumnIndex, columnCount);
                 return;
@@ -625,8 +613,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override Tuple<int, int, T, TOther> Find2Unchecked<TOther>(MatrixStorage<TOther> other, Func<T, TOther, bool> predicate, Zeros zeros)
         {
-            var denseOther = other as DenseColumnMajorMatrixStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseColumnMajorMatrixStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
                 int k = 0;
@@ -644,8 +631,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return null;
             }
 
-            var diagonalOther = other as DiagonalMatrixStorage<TOther>;
-            if (diagonalOther != null)
+            if (other is DiagonalMatrixStorage<TOther> diagonalOther)
             {
                 TOther[] otherData = diagonalOther.Data;
                 for (int i = 0; i < Data.Length; i++)
@@ -666,8 +652,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return null;
             }
 
-            var sparseOther = other as SparseCompressedRowMatrixStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseCompressedRowMatrixStorage<TOther> sparseOther)
             {
                 int[] otherRowPointers = sparseOther.RowPointers;
                 int[] otherColumnIndices = sparseOther.ColumnIndices;
@@ -772,8 +757,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(Zero));
 
-            var diagonalTarget = target as DiagonalMatrixStorage<TU>;
-            if (diagonalTarget != null)
+            if (target is DiagonalMatrixStorage<TU> diagonalTarget)
             {
                 if (processZeros)
                 {
@@ -821,8 +805,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(0, 1, Zero));
 
-            var diagonalTarget = target as DiagonalMatrixStorage<TU>;
-            if (diagonalTarget != null)
+            if (target is DiagonalMatrixStorage<TU> diagonalTarget)
             {
                 if (processZeros)
                 {
@@ -870,15 +853,13 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
             Zeros zeros, ExistingData existingData)
         {
-            var diagonalTarget = target as DiagonalMatrixStorage<TU>;
-            if (diagonalTarget != null)
+            if (target is DiagonalMatrixStorage<TU> diagonalTarget)
             {
                 MapSubMatrixIndexedToUnchecked(diagonalTarget, f, sourceRowIndex, targetRowIndex, rowCount, sourceColumnIndex, targetColumnIndex, columnCount, zeros);
                 return;
             }
 
-            var denseTarget = target as DenseColumnMajorMatrixStorage<TU>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<TU> denseTarget)
             {
                 MapSubMatrixIndexedToUnchecked(denseTarget, f, sourceRowIndex, targetRowIndex, rowCount, sourceColumnIndex, targetColumnIndex, columnCount, zeros, existingData);
                 return;
@@ -1097,8 +1078,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override TState Fold2Unchecked<TOther, TState>(MatrixStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros)
         {
-            var denseOther = other as DenseColumnMajorMatrixStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseColumnMajorMatrixStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
                 int k = 0;
@@ -1113,8 +1093,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return state;
             }
 
-            var diagonalOther = other as DiagonalMatrixStorage<TOther>;
-            if (diagonalOther != null)
+            if (other is DiagonalMatrixStorage<TOther> diagonalOther)
             {
                 TOther[] otherData = diagonalOther.Data;
                 for (int i = 0; i < Data.Length; i++)
@@ -1136,8 +1115,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return state;
             }
 
-            var sparseOther = other as SparseCompressedRowMatrixStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseCompressedRowMatrixStorage<TOther> sparseOther)
             {
                 int[] otherRowPointers = sparseOther.RowPointers;
                 int[] otherColumnIndices = sparseOther.ColumnIndices;

src/Numerics/LinearAlgebra/Storage/SparseCompressedRowMatrixStorage.cs

@@ -69,10 +69,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         /// Gets the number of non zero elements in the matrix.
         /// </summary>
         /// <value>The number of non zero elements.</value>
-        public int ValueCount
-        {
-            get { return RowPointers[RowCount]; }
-        }
+        public int ValueCount => RowPointers[RowCount];
 
         internal SparseCompressedRowMatrixStorage(int rows, int columns)
             : base(rows, columns)
@@ -85,19 +82,13 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         /// <summary>
         /// True if the matrix storage format is dense.
         /// </summary>
-        public override bool IsDense
-        {
-            get { return false; }
-        }
+        public override bool IsDense => false;
 
         /// <summary>
         /// True if all fields of this matrix can be set to any value.
         /// False if some fields are fixed, like on a diagonal matrix.
         /// </summary>
-        public override bool IsFullyMutable
-        {
-            get { return true; }
-        }
+        public override bool IsFullyMutable => true;
 
         /// <summary>
         /// True if the specified field can be set to any value.
@@ -842,15 +833,13 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void CopyToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
-            var sparseTarget = target as SparseCompressedRowMatrixStorage<T>;
-            if (sparseTarget != null)
+            if (target is SparseCompressedRowMatrixStorage<T> sparseTarget)
             {
                 CopyToUnchecked(sparseTarget);
                 return;
             }
 
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 CopyToUnchecked(denseTarget, existingData);
                 return;
@@ -923,8 +912,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 throw new ArgumentNullException(nameof(target));
             }
 
-            var sparseTarget = target as SparseCompressedRowMatrixStorage<T>;
-            if (sparseTarget != null)
+            if (target is SparseCompressedRowMatrixStorage<T> sparseTarget)
             {
                 CopySubMatrixToUnchecked(sparseTarget,
                     sourceRowIndex, targetRowIndex, rowCount,
@@ -1046,8 +1034,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return;
             }
 
-            var targetSparse = target as SparseVectorStorage<T>;
-            if (targetSparse != null)
+            if (target is SparseVectorStorage<T> targetSparse)
             {
                 if ((sourceColumnIndex == 0) && (targetColumnIndex == 0) && (columnCount == ColumnCount) && (ColumnCount == targetSparse.Length))
                 {
@@ -1132,15 +1119,13 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void TransposeToUnchecked(MatrixStorage<T> target, ExistingData existingData)
         {
-            var sparseTarget = target as SparseCompressedRowMatrixStorage<T>;
-            if (sparseTarget != null)
+            if (target is SparseCompressedRowMatrixStorage<T> sparseTarget)
             {
                 TransposeToUnchecked(sparseTarget);
                 return;
             }
 
-            var denseTarget = target as DenseColumnMajorMatrixStorage<T>;
-            if (denseTarget != null)
+            if (target is DenseColumnMajorMatrixStorage<T> denseTarget)
             {
                 TransposeToUnchecked(denseTarget, existingData);
                 return;
@@ -1459,8 +1444,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override Tuple<int, int, T, TOther> Find2Unchecked<TOther>(MatrixStorage<TOther> other, Func<T, TOther, bool> predicate, Zeros zeros)
         {
-            var denseOther = other as DenseColumnMajorMatrixStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseColumnMajorMatrixStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
                 int k = 0;
@@ -1478,8 +1462,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return null;
             }
 
-            var diagonalOther = other as DiagonalMatrixStorage<TOther>;
-            if (diagonalOther != null)
+            if (other is DiagonalMatrixStorage<TOther> diagonalOther)
             {
                 TOther[] otherData = diagonalOther.Data;
                 TOther otherZero = BuilderInstance<TOther>.Matrix.Zero;
@@ -1537,8 +1520,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return null;
             }
 
-            var sparseOther = other as SparseCompressedRowMatrixStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseCompressedRowMatrixStorage<TOther> sparseOther)
             {
                 int[] otherRowPointers = sparseOther.RowPointers;
                 int[] otherColumnIndices = sparseOther.ColumnIndices;
@@ -1714,8 +1696,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(Zero));
 
-            var sparseTarget = target as SparseCompressedRowMatrixStorage<TU>;
-            if (sparseTarget != null)
+            if (target is SparseCompressedRowMatrixStorage<TU> sparseTarget)
             {
                 var newRowPointers = sparseTarget.RowPointers;
                 var newColumnIndices = new List<int>(ColumnIndices.Length);
@@ -1808,8 +1789,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         {
             var processZeros = zeros == Zeros.Include || !Zero.Equals(f(0, 1, Zero));
 
-            var sparseTarget = target as SparseCompressedRowMatrixStorage<TU>;
-            if (sparseTarget != null)
+            if (target is SparseCompressedRowMatrixStorage<TU> sparseTarget)
             {
                 var newRowPointers = sparseTarget.RowPointers;
                 var newColumnIndices = new List<int>(ColumnIndices.Length);
@@ -1903,8 +1883,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             int sourceColumnIndex, int targetColumnIndex, int columnCount,
             Zeros zeros, ExistingData existingData)
         {
-            var sparseTarget = target as SparseCompressedRowMatrixStorage<TU>;
-            if (sparseTarget != null)
+            if (target is SparseCompressedRowMatrixStorage<TU> sparseTarget)
             {
                 MapSubMatrixIndexedToUnchecked(sparseTarget, f, sourceRowIndex, targetRowIndex, rowCount, sourceColumnIndex, targetColumnIndex, columnCount, zeros, existingData);
                 return;
@@ -2203,8 +2182,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override TState Fold2Unchecked<TOther, TState>(MatrixStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros)
         {
-            var denseOther = other as DenseColumnMajorMatrixStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseColumnMajorMatrixStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
                 int k = 0;
@@ -2219,8 +2197,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return state;
             }
 
-            var diagonalOther = other as DiagonalMatrixStorage<TOther>;
-            if (diagonalOther != null)
+            if (other is DiagonalMatrixStorage<TOther> diagonalOther)
             {
                 TOther[] otherData = diagonalOther.Data;
                 TOther otherZero = BuilderInstance<TOther>.Matrix.Zero;
@@ -2266,8 +2243,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return state;
             }
 
-            var sparseOther = other as SparseCompressedRowMatrixStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseCompressedRowMatrixStorage<TOther> sparseOther)
             {
                 int[] otherRowPointers = sparseOther.RowPointers;
                 int[] otherColumnIndices = sparseOther.ColumnIndices;

src/Numerics/LinearAlgebra/Storage/SparseVectorStorage.cs

@@ -73,10 +73,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         /// <summary>
         /// True if the vector storage format is dense.
         /// </summary>
-        public override bool IsDense
-        {
-            get { return false; }
-        }
+        public override bool IsDense => false;
 
         /// <summary>
         /// Retrieves the requested element without range checking.
@@ -425,8 +422,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void CopyToUnchecked(VectorStorage<T> target, ExistingData existingData)
         {
-            var sparseTarget = target as SparseVectorStorage<T>;
-            if (sparseTarget != null)
+            if (target is SparseVectorStorage<T> sparseTarget)
             {
                 CopyToUnchecked(sparseTarget);
                 return;
@@ -517,8 +513,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         internal override void CopySubVectorToUnchecked(VectorStorage<T> target,
             int sourceIndex, int targetIndex, int count, ExistingData existingData)
         {
-            var sparseTarget = target as SparseVectorStorage<T>;
-            if (sparseTarget != null)
+            if (target is SparseVectorStorage<T> sparseTarget)
             {
                 CopySubVectorToUnchecked(sparseTarget, sourceIndex, targetIndex, count, existingData);
                 return;
@@ -689,8 +684,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override Tuple<int, T, TOther> Find2Unchecked<TOther>(VectorStorage<TOther> other, Func<T, TOther, bool> predicate, Zeros zeros)
         {
-            var denseOther = other as DenseVectorStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseVectorStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
                 int k = 0;
@@ -715,8 +709,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return null;
             }
 
-            var sparseOther = other as SparseVectorStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseVectorStorage<TOther> sparseOther)
             {
                 int[] otherIndices = sparseOther.Indices;
                 TOther[] otherValues = sparseOther.Values;
@@ -846,8 +839,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void MapToUnchecked<TU>(VectorStorage<TU> target, Func<T, TU> f, Zeros zeros, ExistingData existingData)
         {
-            var sparseTarget = target as SparseVectorStorage<TU>;
-            if (sparseTarget != null)
+            if (target is SparseVectorStorage<TU> sparseTarget)
             {
                 var indices = new List<int>();
                 var values = new List<TU>();
@@ -882,8 +874,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return;
             }
 
-            var denseTarget = target as DenseVectorStorage<TU>;
-            if (denseTarget != null)
+            if (target is DenseVectorStorage<TU> denseTarget)
             {
                 if (existingData == ExistingData.Clear)
                 {
@@ -920,8 +911,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override void MapIndexedToUnchecked<TU>(VectorStorage<TU> target, Func<int, T, TU> f, Zeros zeros, ExistingData existingData)
         {
-            var sparseTarget = target as SparseVectorStorage<TU>;
-            if (sparseTarget != null)
+            if (target is SparseVectorStorage<TU> sparseTarget)
             {
                 var indices = new List<int>();
                 var values = new List<TU>();
@@ -956,8 +946,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return;
             }
 
-            var denseTarget = target as DenseVectorStorage<TU>;
-            if (denseTarget != null)
+            if (target is DenseVectorStorage<TU> denseTarget)
             {
                 if (existingData == ExistingData.Clear)
                 {
@@ -1083,8 +1072,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return;
             }
 
-            var sparseTarget = target as SparseVectorStorage<T>;
-            if (sparseOther != null && sparseTarget != null)
+            if (sparseOther != null && target is SparseVectorStorage<T> sparseTarget)
             {
                 var indices = new List<int>();
                 var values = new List<T>();
@@ -1146,8 +1134,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
 
         internal override TState Fold2Unchecked<TOther, TState>(VectorStorage<TOther> other, Func<TState, T, TOther, TState> f, TState state, Zeros zeros)
         {
-            var sparseOther = other as SparseVectorStorage<TOther>;
-            if (sparseOther != null)
+            if (other is SparseVectorStorage<TOther> sparseOther)
             {
                 int[] otherIndices = sparseOther.Indices;
                 TOther[] otherValues = sparseOther.Values;
@@ -1192,8 +1179,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
                 return state;
             }
 
-            var denseOther = other as DenseVectorStorage<TOther>;
-            if (denseOther != null)
+            if (other is DenseVectorStorage<TOther> denseOther)
             {
                 TOther[] otherData = denseOther.Data;
 

src/Numerics/LinearAlgebra/Vector.BCL.cs

@@ -62,8 +62,7 @@ namespace MathNet.Numerics.LinearAlgebra
         /// </returns>
         public sealed override bool Equals(object obj)
         {
-            var other = obj as Vector<T>;
-            return other != null && Storage.Equals(other.Storage);
+            return obj is Vector<T> other && Storage.Equals(other.Storage);
         }
 
         /// <summary>
@@ -112,10 +111,7 @@ namespace MathNet.Numerics.LinearAlgebra
             throw new NotSupportedException();
         }
 
-        bool ICollection<T>.IsReadOnly
-        {
-            get { return false; }
-        }
+        bool ICollection<T>.IsReadOnly => false;
 
         void ICollection<T>.Add(T item)
         {
@@ -148,20 +144,14 @@ namespace MathNet.Numerics.LinearAlgebra
             Storage.CopySubVectorTo(new DenseVectorStorage<T>(array.Length, array), 0, arrayIndex, Count);
         }
 
-        bool IList.IsReadOnly
-        {
-            get { return false; }
-        }
+        bool IList.IsReadOnly => false;
 
-        bool IList.IsFixedSize
-        {
-            get { return true; }
-        }
+        bool IList.IsFixedSize => true;
 
         object IList.this[int index]
         {
-            get { return Storage[index]; }
-            set { Storage[index] = (T) value; }
+            get => Storage[index];
+            set => Storage[index] = (T) value;
         }
 
         int IList.IndexOf(object value)
@@ -204,15 +194,9 @@ namespace MathNet.Numerics.LinearAlgebra
             throw new NotSupportedException();
         }
 
-        bool ICollection.IsSynchronized
-        {
-            get { return false; }
-        }
+        bool ICollection.IsSynchronized => false;
 
-        object ICollection.SyncRoot
-        {
-            get { return Storage; }
-        }
+        object ICollection.SyncRoot => Storage;
 
         void ICollection.CopyTo(Array array, int index)
         {
@@ -255,7 +239,7 @@ namespace MathNet.Numerics.LinearAlgebra
         /// </summary>
         public virtual string ToTypeString()
         {
-            return string.Format("{0} {1}-{2}", GetType().Name, Count, typeof (T).Name);
+            return FormattableString.Invariant($"{GetType().Name} {Count}-{typeof(T).Name}");
         }
 
         public string[,] ToVectorStringArray(int maxPerColumn, int maxCharactersWidth, int padding, string ellipsis, Func<T, string> formatValue)

src/Numerics/Optimization/BfgsBMinimizer.cs

@@ -157,7 +157,7 @@ namespace MathNet.Numerics.Optimization
             int iterations = DoBfgsUpdate(ref currentExitCondition, lineSearcher, ref pseudoHessian, ref lineSearchDirection, ref previousPoint, ref lineSearchResult, ref candidatePoint, ref step, ref totalLineSearchSteps, ref iterationsWithNontrivialLineSearch);
 
             if (iterations == MaximumIterations && currentExitCondition == ExitCondition.None)
-                throw new MaximumIterationsException(string.Format("Maximum iterations ({0}) reached.", MaximumIterations));
+                throw new MaximumIterationsException(FormattableString.Invariant($"Maximum iterations ({MaximumIterations}) reached."));
 
             return new MinimizationWithLineSearchResult(candidatePoint, iterations, currentExitCondition, totalLineSearchSteps, iterationsWithNontrivialLineSearch);
         }

src/Numerics/Optimization/BfgsMinimizer.cs

@@ -107,7 +107,7 @@ namespace MathNet.Numerics.Optimization
             iterations = DoBfgsUpdate(ref currentExitCondition, lineSearcher, ref inversePseudoHessian, ref lineSearchDirection, ref previousPoint, ref lineSearchResult, ref candidate, ref step, ref totalLineSearchSteps, ref iterationsWithNontrivialLineSearch);
 
             if (iterations == MaximumIterations && currentExitCondition == ExitCondition.None)
-                throw new MaximumIterationsException(String.Format("Maximum iterations ({0}) reached.", MaximumIterations));
+                throw new MaximumIterationsException(FormattableString.Invariant($"Maximum iterations ({MaximumIterations}) reached."));
 
             return new MinimizationWithLineSearchResult(candidate, iterations, ExitCondition.AbsoluteGradient, totalLineSearchSteps, iterationsWithNontrivialLineSearch);
         }

src/Numerics/Optimization/ConjugateGradientMinimizer.cs

@@ -124,7 +124,7 @@ namespace MathNet.Numerics.Optimization
 
             if (iterations == maxIterations)
             {
-                throw new MaximumIterationsException(String.Format("Maximum iterations ({0}) reached.", maxIterations));
+                throw new MaximumIterationsException(FormattableString.Invariant($"Maximum iterations ({maxIterations}) reached."));
             }
 
             return new MinimizationWithLineSearchResult(objective, iterations, ExitCondition.AbsoluteGradient, totalLineSearchSteps, iterationsWithNontrivialLineSearch);

src/Numerics/Optimization/LimitedMemoryBfgsMinimizer.cs

@@ -150,7 +150,7 @@ namespace MathNet.Numerics.Optimization
             }
 
             if (iterations == MaximumIterations && currentExitCondition == ExitCondition.None)
-                throw new MaximumIterationsException(String.Format("Maximum iterations ({0}) reached.", MaximumIterations));
+                throw new MaximumIterationsException(FormattableString.Invariant($"Maximum iterations ({MaximumIterations}) reached."));
 
             return new MinimizationWithLineSearchResult(candidate, iterations, ExitCondition.AbsoluteGradient, totalLineSearchSteps, iterationsWithNontrivialLineSearch);
         }

src/Numerics/Optimization/LineSearch/StrongWolfeLineSearch.cs

@@ -39,10 +39,7 @@ namespace MathNet.Numerics.Optimization.LineSearch
             // Argument validation in base class
         }
 
-        protected override ExitCondition WolfeExitCondition
-        {
-            get { return ExitCondition.StrongWolfeCriteria; }
-        }
+        protected override ExitCondition WolfeExitCondition => ExitCondition.StrongWolfeCriteria;
 
         protected override bool WolfeCondition(double stepDd, double initialDd)
         {

src/Numerics/Optimization/LineSearch/WeakWolfeLineSearch.cs

@@ -53,10 +53,7 @@ namespace MathNet.Numerics.Optimization.LineSearch
             // Validation in base class
         }
 
-        protected override ExitCondition WolfeExitCondition
-        {
-            get { return ExitCondition.WeakWolfeCriteria; }
-        }
+        protected override ExitCondition WolfeExitCondition => ExitCondition.WeakWolfeCriteria;
 
         protected override bool WolfeCondition(double stepDd, double initialDd)
         {
@@ -67,7 +64,7 @@ namespace MathNet.Numerics.Optimization.LineSearch
         {
             if (!IsFinite(eval.Value))
             {
-                throw new EvaluationException(String.Format("Non-finite value returned by objective function: {0}", eval.Value), eval);
+                throw new EvaluationException(FormattableString.Invariant($"Non-finite value returned by objective function: {eval.Value}"), eval);
             }
         }
 
@@ -83,7 +80,7 @@ namespace MathNet.Numerics.Optimization.LineSearch
             {
                 if (!IsFinite(x))
                 {
-                    throw new EvaluationException(string.Format("Non-finite value returned by gradient: {0}", x), eval);
+                    throw new EvaluationException(FormattableString.Invariant($"Non-finite value returned by gradient: {x}"), eval);
                 }
             }
         }

src/Numerics/Optimization/LineSearch/WolfeLineSearch.cs

@@ -29,6 +29,7 @@
 
 using System;
 using MathNet.Numerics.LinearAlgebra;
+using static System.FormattableString;
 
 namespace MathNet.Numerics.Optimization.LineSearch
 {
@@ -42,11 +43,11 @@ namespace MathNet.Numerics.Optimization.LineSearch
         public WolfeLineSearch(double c1, double c2, double parameterTolerance, int maxIterations = 10)
         {
             if (c1 <= 0)
-                throw new ArgumentException(string.Format("c1 {0} should be greater than 0", c1));
+                throw new ArgumentException(Invariant($"c1 {c1} should be greater than 0"));
             if (c2 <= c1)
-                throw new ArgumentException(string.Format("c1 {0} should be less than c2 {1}", c1, c2));
+                throw new ArgumentException(Invariant($"c1 {c1} should be less than c2 {c2}"));
             if (c2 >= 1)
-                throw new ArgumentException(string.Format("c2 {0} should be less than 1", c2));
+                throw new ArgumentException(Invariant($"c2 {c2} should be less than 1"));
 
             C1 = c1;
             C2 = c2;
@@ -125,12 +126,12 @@ namespace MathNet.Numerics.Optimization.LineSearch
 
             if (ii == MaximumIterations && Double.IsPositiveInfinity(upperBound))
             {
-                throw new MaximumIterationsException(String.Format("Maximum iterations ({0}) reached. Function appears to be unbounded in search direction.", MaximumIterations));
+                throw new MaximumIterationsException(Invariant($"Maximum iterations ({MaximumIterations}) reached. Function appears to be unbounded in search direction."));
             }
 
             if (ii == MaximumIterations)
             {
-                throw new MaximumIterationsException(String.Format("Maximum iterations ({0}) reached.", MaximumIterations));
+                throw new MaximumIterationsException(Invariant($"Maximum iterations ({MaximumIterations}) reached."));
             }
 
             return new LineSearchResult(objective, ii, step, reasonForExit);

src/Numerics/Optimization/MinimizationResult.cs

@@ -33,10 +33,10 @@ namespace MathNet.Numerics.Optimization
 {
     public class MinimizationResult
     {
-        public Vector<double> MinimizingPoint { get { return FunctionInfoAtMinimum.Point; } }
-        public IObjectiveFunction FunctionInfoAtMinimum { get; private set; }
-        public int Iterations { get; private set; }
-        public ExitCondition ReasonForExit { get; private set; }
+        public Vector<double> MinimizingPoint => FunctionInfoAtMinimum.Point;
+        public IObjectiveFunction FunctionInfoAtMinimum { get; }
+        public int Iterations { get; }
+        public ExitCondition ReasonForExit { get; }
 
         public MinimizationResult(IObjectiveFunction functionInfo, int iterations, ExitCondition reasonForExit)
         {

src/Numerics/Optimization/NelderMeadSimplex.cs

@@ -180,7 +180,7 @@ namespace MathNet.Numerics.Optimization
                 // check to see if we have exceeded our alloted number of evaluations
                 if (evaluationCount >= maximumIterations)
                 {
-                    throw new MaximumIterationsException(String.Format("Maximum iterations ({0}) reached.", maximumIterations));
+                    throw new MaximumIterationsException(FormattableString.Invariant($"Maximum iterations ({maximumIterations}) reached."));
                 }
             }
             objectiveFunction.EvaluateAt(vertices[errorProfile.LowestIndex]);

src/Numerics/Optimization/NewtonMinimizer.cs

@@ -119,7 +119,7 @@ namespace MathNet.Numerics.Optimization
 
             if (iterations == maxIterations)
             {
-                throw new MaximumIterationsException(String.Format("Maximum iterations ({0}) reached.", maxIterations));
+                throw new MaximumIterationsException(FormattableString.Invariant($"Maximum iterations ({maxIterations}) reached."));
             }
 
             return new MinimizationWithLineSearchResult(objective, iterations, ExitCondition.AbsoluteGradient, totalLineSearchSteps, iterationsWithNontrivialLineSearch);

src/Numerics/Optimization/NonlinearMinimizationResult.cs

@@ -4,22 +4,22 @@ namespace MathNet.Numerics.Optimization
 {
     public class NonlinearMinimizationResult
     {
-        public IObjectiveModel ModelInfoAtMinimum { get; private set; }
+        public IObjectiveModel ModelInfoAtMinimum { get; }
 
         /// <summary>
         /// Returns the best fit parameters.
         /// </summary>
-        public Vector<double> MinimizingPoint { get { return ModelInfoAtMinimum.Point; } }
+        public Vector<double> MinimizingPoint => ModelInfoAtMinimum.Point;
 
         /// <summary>
-        /// Returns the standard errors of the corresponding parameters 
+        /// Returns the standard errors of the corresponding parameters
         /// </summary>
         public Vector<double> StandardErrors { get; private set; }
 
         /// <summary>
         /// Returns the y-values of the fitted model that correspond to the independent values.
         /// </summary>
-        public Vector<double> MinimizedValues { get { return ModelInfoAtMinimum.ModelValues; } }
+        public Vector<double> MinimizedValues => ModelInfoAtMinimum.ModelValues;
 
         /// <summary>
         /// Returns the covariance matrix at minimizing point.
@@ -31,9 +31,9 @@ namespace MathNet.Numerics.Optimization
         /// </summary>
         public Matrix<double> Correlation { get; private set; }
 
-        public int Iterations { get; private set; }
+        public int Iterations { get; }
 
-        public ExitCondition ReasonForExit { get; private set; }
+        public ExitCondition ReasonForExit { get; }
 
         public NonlinearMinimizationResult(IObjectiveModel modelInfo, int iterations, ExitCondition reasonForExit)
         {
@@ -72,7 +72,7 @@ namespace MathNet.Numerics.Optimization
             {
                 StandardErrors = null;
                 Correlation = null;
-            }            
+            }
         }
     }
 }

src/Numerics/Optimization/NonlinearMinimizerBase.cs

@@ -19,8 +19,8 @@ namespace MathNet.Numerics.Optimization
         /// <summary>
         /// The stopping threshold for infinity norm of the gradient.
         /// </summary>
-        public static double GradientTolerance { get; set; }        
-        
+        public static double GradientTolerance { get; set; }
+
         /// <summary>
         /// The maximum number of iterations.
         /// </summary>
@@ -41,7 +41,7 @@ namespace MathNet.Numerics.Optimization
         /// </summary>
         public static Vector<double> Scales { get; private set; }
 
-        private static bool IsBounded { get { return LowerBound != null || UpperBound != null || Scales != null; } }
+        private static bool IsBounded => LowerBound != null || UpperBound != null || Scales != null;
 
         protected NonlinearMinimizerBase(double gradientTolerance = 1E-18, double stepTolerance = 1E-18, double functionTolerance = 1E-18, int maximumIterations = -1)
         {

src/Numerics/Optimization/ObjectiveFunctions/ForwardDifferenceGradientObjectiveFunction.cs

@@ -104,32 +104,14 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
                     EvaluateGradient();
                 return _gradient;
             }
-            protected set { _gradient = value; }
+            protected set => _gradient = value;
         }
 
-        public Matrix<double> Hessian
-        {
-            get
-            {
-                throw new NotImplementedException();
-            }
-        }
+        public Matrix<double> Hessian => throw new NotImplementedException();
 
-        public bool IsGradientSupported
-        {
-            get
-            {
-                return true;
-            }
-        }
+        public bool IsGradientSupported => true;
 
-        public bool IsHessianSupported
-        {
-            get
-            {
-                return false;
-            }
-        }
+        public bool IsHessianSupported => false;
 
         public Vector<double> Point { get; protected set; }
 
@@ -145,7 +127,7 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
 
         public IObjectiveFunction CreateNew()
         {
-            var tmp = new ForwardDifferenceGradientObjectiveFunction(this.InnerObjectiveFunction.CreateNew(), LowerBound, UpperBound, this.RelativeIncrement, this.MinimumIncrement);
+            var tmp = new ForwardDifferenceGradientObjectiveFunction(InnerObjectiveFunction.CreateNew(), LowerBound, UpperBound, this.RelativeIncrement, this.MinimumIncrement);
             return tmp;
         }
 
@@ -159,7 +141,7 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
 
         public IObjectiveFunction Fork()
         {
-            return new ForwardDifferenceGradientObjectiveFunction(this.InnerObjectiveFunction.Fork(), LowerBound, UpperBound, this.RelativeIncrement, this.MinimumIncrement)
+            return new ForwardDifferenceGradientObjectiveFunction(InnerObjectiveFunction.Fork(), LowerBound, UpperBound, this.RelativeIncrement, this.MinimumIncrement)
             {
                 Point = Point?.Clone(),
                 GradientEvaluated = GradientEvaluated,

src/Numerics/Optimization/ObjectiveFunctions/GradientHessianObjectiveFunction.cs

@@ -58,15 +58,9 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             };
         }
 
-        public bool IsGradientSupported
-        {
-            get { return true; }
-        }
+        public bool IsGradientSupported => true;
 
-        public bool IsHessianSupported
-        {
-            get { return true; }
-        }
+        public bool IsHessianSupported => true;
 
         public void EvaluateAt(Vector<double> point)
         {

src/Numerics/Optimization/ObjectiveFunctions/GradientObjectiveFunction.cs

@@ -57,15 +57,9 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             };
         }
 
-        public bool IsGradientSupported
-        {
-            get { return true; }
-        }
+        public bool IsGradientSupported => true;
 
-        public bool IsHessianSupported
-        {
-            get { return false; }
-        }
+        public bool IsHessianSupported => false;
 
         public void EvaluateAt(Vector<double> point)
         {
@@ -80,9 +74,6 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
         public double Value { get; private set; }
         public Vector<double> Gradient { get; private set; }
 
-        public Matrix<double> Hessian
-        {
-            get { throw new NotSupportedException(); }
-        }
+        public Matrix<double> Hessian => throw new NotSupportedException();
     }
 }

src/Numerics/Optimization/ObjectiveFunctions/HessianObjectiveFunction.cs

@@ -57,15 +57,9 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             };
         }
 
-        public bool IsGradientSupported
-        {
-            get { return false; }
-        }
+        public bool IsGradientSupported => false;
 
-        public bool IsHessianSupported
-        {
-            get { return true; }
-        }
+        public bool IsHessianSupported => true;
 
         public void EvaluateAt(Vector<double> point)
         {
@@ -80,9 +74,6 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
         public double Value { get; private set; }
         public Matrix<double> Hessian { get; private set; }
 
-        public Vector<double> Gradient
-        {
-            get { throw new NotSupportedException(); }
-        }
+        public Vector<double> Gradient => throw new NotSupportedException();
     }
 }

src/Numerics/Optimization/ObjectiveFunctions/LazyObjectiveFunction.cs

@@ -94,10 +94,7 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             _hessianValue = null;
         }
 
-        public Vector<double> Point
-        {
-            get { return _point; }
-        }
+        public Vector<double> Point => _point;
 
         public double Value
         {

src/Numerics/Optimization/ObjectiveFunctions/LazyObjectiveFunctionBase.cs

@@ -89,10 +89,7 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             Hessian = null;
         }
 
-        public Vector<double> Point
-        {
-            get { return _point; }
-        }
+        public Vector<double> Point => _point;
 
         public double Value
         {

src/Numerics/Optimization/ObjectiveFunctions/NonlinearObjectiveFunction.cs

@@ -23,7 +23,7 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
         Matrix<double> jacobianValue; // the Jacobian matrix.
         Vector<double> gradientValue; // the Gradient vector.
         Matrix<double> hessianValue; // the Hessian matrix.
-        
+
         #endregion Private Variables
 
         #region Public Variables
@@ -37,7 +37,7 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
         /// Set or get the values of the observations.
         /// </summary>
         public Vector<double> ObservedY { get; private set; }
-        
+
         /// <summary>
         /// Set or get the values of the weights for the observations.
         /// </summary>
@@ -52,12 +52,12 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
         /// <summary>
         /// Get the number of observations.
         /// </summary>
-        public int NumberOfObservations { get { return (ObservedY == null) ? 0 : ObservedY.Count; } }
-        
+        public int NumberOfObservations => ObservedY?.Count ?? 0;
+
         /// <summary>
         /// Get the number of unknown parameters.
         /// </summary>
-        public int NumberOfParameters { get { return (Point == null) ? 0 : Point.Count; } }
+        public int NumberOfParameters => Point?.Count ?? 0;
 
         /// <summary>
         /// Get the degree of freedom
@@ -123,7 +123,7 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
         /// <summary>
         /// Set or get the values of the parameters.
         /// </summary>
-        public Vector<double> Point { get { return coefficients; } }
+        public Vector<double> Point => coefficients;
 
         /// <summary>
         /// Get the y-values of the fitted model that correspond to the independent values.
@@ -178,8 +178,8 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             }
         }
 
-        public bool IsGradientSupported { get { return true; } }
-        public bool IsHessianSupported { get { return true; } }
+        public bool IsGradientSupported => true;
+        public bool IsHessianSupported => true;
 
         /// <summary>
         /// Set observed data to fit.
@@ -235,7 +235,7 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
                 throw new ArgumentNullException("initialGuess");
             }
             coefficients = initialGuess;
-            
+
             if (isFixed != null && isFixed.Count != initialGuess.Count)
             {
                 throw new ArgumentException("The isFixed can't have different size from the initial guess.");
@@ -342,11 +342,11 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             // approximated Hessian, H = J'WJ + ∑LRiHi ~ J'WJ near the minimum
             hessianValue = jacobianValue.Transpose() * jacobianValue;
         }
-        
+
         private Matrix<double> NumericalJacobian(Vector<double> parameters, Vector<double> currentValues, int accuracyOrder = 2)
-        {   
+        {
             const double sqrtEpsilon = 1.4901161193847656250E-8; // sqrt(machineEpsilon)
-            
+
             Matrix<double> derivertives = Matrix<double>.Build.Dense(NumberOfObservations, NumberOfParameters);
 
             var d = 0.000003 * parameters.PointwiseAbs().PointwiseMaximum(sqrtEpsilon);

src/Numerics/Optimization/ObjectiveFunctions/ScalarObjectiveFunction.cs

@@ -63,17 +63,17 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             return _secondDerivative.Value;
         }
 
-        public double Point { get { return _point; } }
-        public double Value { get { return _value ?? SetValue(); } }
-        public double Derivative { get { return _derivative ?? SetDerivative(); } }
-        public double SecondDerivative { get { return _secondDerivative ?? SetSecondDerivative(); } }
+        public double Point => _point;
+        public double Value => _value ?? SetValue();
+        public double Derivative => _derivative ?? SetDerivative();
+        public double SecondDerivative => _secondDerivative ?? SetSecondDerivative();
     }
 
     internal class ScalarObjectiveFunction : IScalarObjectiveFunction
     {
-        public Func<double, double> Objective { get; private set; }
-        public Func<double, double> Derivative { get; private set; }
-        public Func<double, double> SecondDerivative { get; private set; }
+        public Func<double, double> Objective { get; }
+        public Func<double, double> Derivative { get; }
+        public Func<double, double> SecondDerivative { get; }
 
         public ScalarObjectiveFunction(Func<double, double> objective)
         {
@@ -96,15 +96,9 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             SecondDerivative = secondDerivative;
         }
 
-        public bool IsDerivativeSupported
-        {
-            get { return Derivative != null; }
-        }
+        public bool IsDerivativeSupported => Derivative != null;
 
-        public bool IsSecondDerivativeSupported
-        {
-            get { return SecondDerivative != null; }
-        }
+        public bool IsSecondDerivativeSupported => SecondDerivative != null;
 
         public IScalarObjectiveFunctionEvaluation Evaluate(double point)
         {

src/Numerics/Optimization/ObjectiveFunctions/ScalarValueObjectiveFunction.cs

@@ -42,35 +42,23 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
         public double Point { get; }
         public double Value { get; }
 
-        public double Derivative
-        {
-            get { throw new NotSupportedException(); }
-        }
+        public double Derivative => throw new NotSupportedException();
 
-        public double SecondDerivative
-        {
-            get { throw new NotSupportedException(); }
-        }
+        public double SecondDerivative => throw new NotSupportedException();
     }
 
     internal class ScalarValueObjectiveFunction : IScalarObjectiveFunction
     {
-        public Func<double, double> Objective { get; private set; }
+        public Func<double, double> Objective { get; }
 
         public ScalarValueObjectiveFunction(Func<double, double> objective)
         {
             Objective = objective;
         }
 
-        public bool IsDerivativeSupported
-        {
-            get { return false; }
-        }
+        public bool IsDerivativeSupported => false;
 
-        public bool IsSecondDerivativeSupported
-        {
-            get { return false; }
-        }
+        public bool IsSecondDerivativeSupported => false;
 
         public IScalarObjectiveFunctionEvaluation Evaluate(double point)
         {

src/Numerics/Optimization/ObjectiveFunctions/ValueObjectiveFunction.cs

@@ -56,15 +56,9 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
             };
         }
 
-        public bool IsGradientSupported
-        {
-            get { return false; }
-        }
+        public bool IsGradientSupported => false;
 
-        public bool IsHessianSupported
-        {
-            get { return false; }
-        }
+        public bool IsHessianSupported => false;
 
         public void EvaluateAt(Vector<double> point)
         {
@@ -75,14 +69,8 @@ namespace MathNet.Numerics.Optimization.ObjectiveFunctions
         public Vector<double> Point { get; private set; }
         public double Value { get; private set; }
 
-        public Matrix<double> Hessian
-        {
-            get { throw new NotSupportedException(); }
-        }
+        public Matrix<double> Hessian => throw new NotSupportedException();
 
-        public Vector<double> Gradient
-        {
-            get { throw new NotSupportedException(); }
-        }
+        public Vector<double> Gradient => throw new NotSupportedException();
     }
 }

src/Numerics/Optimization/ScalarMinimizationResult.cs

@@ -31,10 +31,10 @@ namespace MathNet.Numerics.Optimization
 {
     public class ScalarMinimizationResult
     {
-        public double MinimizingPoint { get { return FunctionInfoAtMinimum.Point; } }
-        public IScalarObjectiveFunctionEvaluation FunctionInfoAtMinimum { get; private set; }
-        public int Iterations { get; private set; }
-        public ExitCondition ReasonForExit { get; private set; }
+        public double MinimizingPoint => FunctionInfoAtMinimum.Point;
+        public IScalarObjectiveFunctionEvaluation FunctionInfoAtMinimum { get; }
+        public int Iterations { get; }
+        public ExitCondition ReasonForExit { get; }
 
         public ScalarMinimizationResult(IScalarObjectiveFunctionEvaluation functionInfo, int iterations, ExitCondition reasonForExit)
         {

src/Numerics/Permutation.cs

@@ -69,23 +69,14 @@ namespace MathNet.Numerics
         /// <summary>
         /// Gets the number of elements this permutation is over.
         /// </summary>
-        public int Dimension
-        {
-            get { return _indices.Length; }
-        }
+        public int Dimension => _indices.Length;
 
         /// <summary>
         /// Computes where <paramref name="idx"/> permutes too.
         /// </summary>
         /// <param name="idx">The index to permute from.</param>
         /// <returns>The index which is permuted to.</returns>
-        public int this[int idx]
-        {
-            get
-            {
-                return _indices[idx];
-            }
-        }
+        public int this[int idx] => _indices[idx];
 
         /// <summary>
         /// Computes the inverse of the permutation.

src/Numerics/Providers/Common/Cuda/SafeNativeMethods.cs

@@ -49,7 +49,7 @@ namespace MathNet.Numerics.Providers.Common.Cuda
         /// Name of the native DLL.
         /// </summary>
         const string _DllName = "MathNet.Numerics.CUDA.dll";
-        internal static string DllName { get { return _DllName; } }
+        internal static string DllName => _DllName;
 
         [DllImport(_DllName, ExactSpelling = true, SetLastError = false, CallingConvention = CallingConvention.Cdecl)]
         internal static extern int query_capability(int capability);