LA: Vector.Negate should implement common pattern

src/Numerics/LinearAlgebra/Complex/DenseVector.cs

@@ -369,19 +369,20 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>The negated vector.</returns>
-        /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public override Vector<Complex> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<Complex> target)
         {
-            var result = new DenseVector(_length);
-            CommonParallel.For(
-                0, 
-                _values.Length,
-                index => result[index] = -_values[index]);
-
-            return result;
+            var denseResult = target as DenseVector;
+            if (denseResult == null)
+            {
+                base.DoNegate(target);
+            }
+            else
+            {
+                Control.LinearAlgebraProvider.ScaleArray(-Complex.One, _values, denseResult.Values);
+            }
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex/SparseVector.cs

@@ -448,24 +448,33 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>The negated vector.</returns>
-        /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public override Vector<Complex> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<Complex> target)
         {
-            var result = new SparseVectorStorage<Complex>(Count);
-            var valueCount = result.ValueCount = _storage.ValueCount;
-            var indices = result.Indices = new int[valueCount];
-            var values = result.Values = new Complex[valueCount];
-
-            if (valueCount != 0)
+            var sparseResult = target as SparseVector;
+            if (sparseResult == null)
             {
-                CommonParallel.For(0, valueCount, index => values[index] = -_storage.Values[index]);
-                Buffer.BlockCopy(_storage.Indices, 0, indices, 0, valueCount * Constants.SizeOfInt);
+                target.Clear();
+                for (var index = 0; index < _storage.ValueCount; index++)
+                {
+                    target.At(_storage.Indices[index], -_storage.Values[index]);
+                }
             }
+            else
+            {
+                if (!ReferenceEquals(this, target))
+                {
+                    sparseResult._storage.ValueCount = _storage.ValueCount;
+                    sparseResult._storage.Indices = new int[_storage.ValueCount];
+                    Buffer.BlockCopy(_storage.Indices, 0, sparseResult._storage.Indices, 0, _storage.ValueCount * Constants.SizeOfInt);
+                    sparseResult._storage.Values = new Complex[_storage.ValueCount];
+                    Array.Copy(_storage.Values, sparseResult._storage.Values, _storage.ValueCount);
+                }
 
-            return new SparseVector(result);
+                Control.LinearAlgebraProvider.ScaleArray(-Complex.One, sparseResult._storage.Values, sparseResult._storage.Values);
+            }
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex/Vector.cs

@@ -339,24 +339,15 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>
-        /// The negated vector.
-        /// </returns>
-        /// <remarks>
-        /// Added as an alternative to the unary negation operator.
-        /// </remarks>
-        public override Vector<Complex> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<Complex> target)
         {
-            var result = CreateVector(Count);
-
             for (var index = 0; index < Count; index++)
             {
-                result.At(index, -At(index));
+                target.At(index, -At(index));
             }
-
-            return result;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex32/DenseVector.cs

@@ -369,19 +369,20 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>The negated vector.</returns>
-        /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public override Vector<Complex32> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<Complex32> target)
         {
-            var result = new DenseVector(_length);
-            CommonParallel.For(
-                0, 
-                _values.Length,
-                index => result[index] = -_values[index]);
-
-            return result;
+            var denseResult = target as DenseVector;
+            if (denseResult == null)
+            {
+                base.DoNegate(target);
+            }
+            else
+            {
+                Control.LinearAlgebraProvider.ScaleArray(-Complex32.One, _values, denseResult.Values);
+            }
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex32/SparseVector.cs

@@ -448,24 +448,33 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>The negated vector.</returns>
-        /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public override Vector<Complex32> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<Complex32> target)
         {
-            var result = new SparseVectorStorage<Complex32>(Count);
-            var valueCount = result.ValueCount = _storage.ValueCount;
-            var indices = result.Indices = new int[valueCount];
-            var values = result.Values = new Complex32[valueCount];
-
-            if (valueCount != 0)
+            var sparseResult = target as SparseVector;
+            if (sparseResult == null)
             {
-                CommonParallel.For(0, valueCount, index => values[index] = -_storage.Values[index]);
-                Buffer.BlockCopy(_storage.Indices, 0, indices, 0, valueCount * Constants.SizeOfInt);
+                target.Clear();
+                for (var index = 0; index < _storage.ValueCount; index++)
+                {
+                    target.At(_storage.Indices[index], -_storage.Values[index]);
+                }
             }
+            else
+            {
+                if (!ReferenceEquals(this, target))
+                {
+                    sparseResult._storage.ValueCount = _storage.ValueCount;
+                    sparseResult._storage.Indices = new int[_storage.ValueCount];
+                    Buffer.BlockCopy(_storage.Indices, 0, sparseResult._storage.Indices, 0, _storage.ValueCount * Constants.SizeOfInt);
+                    sparseResult._storage.Values = new Complex32[_storage.ValueCount];
+                    Array.Copy(_storage.Values, sparseResult._storage.Values, _storage.ValueCount);
+                }
 
-            return new SparseVector(result);
+                Control.LinearAlgebraProvider.ScaleArray(-Complex32.One, sparseResult._storage.Values, sparseResult._storage.Values);
+            }
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex32/Vector.cs

@@ -339,24 +339,15 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>
-        /// The negated vector.
-        /// </returns>
-        /// <remarks>
-        /// Added as an alternative to the unary negation operator.
-        /// </remarks>
-        public override Vector<Complex32> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<Complex32> target)
         {
-            var result = CreateVector(Count);
-
             for (var index = 0; index < Count; index++)
             {
-                result.At(index, -At(index));
+                target.At(index, -At(index));
             }
-
-            return result;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Double/DenseVector.cs

@@ -379,19 +379,20 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>The negated vector.</returns>
-        /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public override Vector<double> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<double> target)
         {
-            var result = new DenseVector(_length);
-            CommonParallel.For(
-                0, 
-                _values.Length,
-                index => result[index] = -_values[index]);
-
-            return result;
+            var denseResult = target as DenseVector;
+            if (denseResult == null)
+            {
+                base.DoNegate(target);
+            }
+            else
+            {
+                Control.LinearAlgebraProvider.ScaleArray(-1.0d, _values, denseResult.Values);
+            }
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Double/SparseVector.cs

@@ -416,24 +416,33 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>The negated vector.</returns>
-        /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public override Vector<double> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<double> target)
         {
-            var result = new SparseVectorStorage<double>(Count);
-            var valueCount = result.ValueCount = _storage.ValueCount;
-            var indices = result.Indices = new int[valueCount];
-            var values = result.Values = new double[valueCount];
-
-            if (valueCount != 0)
+            var sparseResult = target as SparseVector;
+            if (sparseResult == null)
             {
-                CommonParallel.For(0, valueCount, index => values[index] = -_storage.Values[index]);
-                Buffer.BlockCopy(_storage.Indices, 0, indices, 0, valueCount * Constants.SizeOfInt);
+                target.Clear();
+                for (var index = 0; index < _storage.ValueCount; index++)
+                {
+                    target.At(_storage.Indices[index], -_storage.Values[index]);
+                }
             }
+            else
+            {
+                if (!ReferenceEquals(this, target))
+                {
+                    sparseResult._storage.ValueCount = _storage.ValueCount;
+                    sparseResult._storage.Indices = new int[_storage.ValueCount];
+                    Buffer.BlockCopy(_storage.Indices, 0, sparseResult._storage.Indices, 0, _storage.ValueCount * Constants.SizeOfInt);
+                    sparseResult._storage.Values = new double[_storage.ValueCount];
+                    Array.Copy(_storage.Values, sparseResult._storage.Values, _storage.ValueCount);
+                }
 
-            return new SparseVector(result);
+                Control.LinearAlgebraProvider.ScaleArray(-1.0d, sparseResult._storage.Values, sparseResult._storage.Values);
+            }
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Double/Vector.cs

@@ -343,24 +343,15 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>
-        /// The negated vector.
-        /// </returns>
-        /// <remarks>
-        /// Added as an alternative to the unary negation operator.
-        /// </remarks>
-        public override Vector<double> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<double> target)
         {
-            var result = CreateVector(Count);
-
             for (var index = 0; index < Count; index++)
             {
-                result.At(index, -At(index));
+                target.At(index, -At(index));
             }
-
-            return result;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Generic/Vector.cs

@@ -335,7 +335,37 @@ namespace MathNet.Numerics.LinearAlgebra.Generic
         /// </summary>
         /// <returns>The negated vector.</returns>
         /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public abstract Vector<T> Negate();
+        public Vector<T> Negate()
+        {
+            var retrunVector = CreateVector(Count);
+            DoNegate(retrunVector);
+            return retrunVector;
+        }
+
+        /// <summary>
+        /// Negates vector and save result to <paramref name="target"/>
+        /// </summary>
+        /// <param name="target">Target vector</param>
+        public void Negate(Vector<T> target)
+        {
+            if (target == null)
+            {
+                throw new ArgumentNullException("target");
+            }
+
+            if (Count != target.Count)
+            {
+                throw new ArgumentException(Resources.ArgumentVectorsSameLength, "target");
+            }
+
+            DoNegate(target);
+        }
+
+        /// <summary>
+        /// Negates vector and save result to <paramref name="target"/>
+        /// </summary>
+        /// <param name="target">Target vector</param>
+        protected abstract void DoNegate(Vector<T> target);
 
         /// <summary>
         /// Subtracts another vector from this vector.
@@ -399,7 +429,7 @@ namespace MathNet.Numerics.LinearAlgebra.Generic
         public Vector<T> Conjugate()
         {
             var retrunVector = CreateVector(Count);
-            Conjugate(retrunVector);
+            DoConjugate(retrunVector);
             return retrunVector;
         }
 

src/Numerics/LinearAlgebra/Single/DenseVector.cs

@@ -369,19 +369,20 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>The negated vector.</returns>
-        /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public override Vector<float> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<float> target)
         {
-            var result = new DenseVector(_length);
-            CommonParallel.For(
-                0, 
-                _values.Length,
-                index => result[index] = -_values[index]);
-
-            return result;
+            var denseResult = target as DenseVector;
+            if (denseResult == null)
+            {
+                base.DoNegate(target);
+            }
+            else
+            {
+                Control.LinearAlgebraProvider.ScaleArray(-1.0f, _values, denseResult.Values);
+            }
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Single/SparseVector.cs

@@ -417,24 +417,33 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>The negated vector.</returns>
-        /// <remarks>Added as an alternative to the unary negation operator.</remarks>
-        public override Vector<float> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<float> target)
         {
-            var result = new SparseVectorStorage<float>(Count);
-            var valueCount = result.ValueCount = _storage.ValueCount;
-            var indices = result.Indices = new int[valueCount];
-            var values = result.Values = new float[valueCount];
-
-            if (valueCount != 0)
+            var sparseResult = target as SparseVector;
+            if (sparseResult == null)
             {
-                CommonParallel.For(0, valueCount, index => values[index] = -_storage.Values[index]);
-                Buffer.BlockCopy(_storage.Indices, 0, indices, 0, valueCount * Constants.SizeOfInt);
+                target.Clear();
+                for (var index = 0; index < _storage.ValueCount; index++)
+                {
+                    target.At(_storage.Indices[index], -_storage.Values[index]);
+                }
             }
+            else
+            {
+                if (!ReferenceEquals(this, target))
+                {
+                    sparseResult._storage.ValueCount = _storage.ValueCount;
+                    sparseResult._storage.Indices = new int[_storage.ValueCount];
+                    Buffer.BlockCopy(_storage.Indices, 0, sparseResult._storage.Indices, 0, _storage.ValueCount * Constants.SizeOfInt);
+                    sparseResult._storage.Values = new float[_storage.ValueCount];
+                    Array.Copy(_storage.Values, sparseResult._storage.Values, _storage.ValueCount);
+                }
 
-            return new SparseVector(result);
+                Control.LinearAlgebraProvider.ScaleArray(-1.0f, sparseResult._storage.Values, sparseResult._storage.Values);
+            }
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Single/Vector.cs

@@ -343,24 +343,15 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         }
 
         /// <summary>
-        /// Returns a negated vector.
+        /// Negates vector and saves result to <paramref name="target"/>
         /// </summary>
-        /// <returns>
-        /// The negated vector.
-        /// </returns>
-        /// <remarks>
-        /// Added as an alternative to the unary negation operator.
-        /// </remarks>
-        public override Vector<float> Negate()
+        /// <param name="target">Target vector</param>
+        protected override void DoNegate(Vector<float> target)
         {
-            var result = CreateVector(Count);
-
             for (var index = 0; index < Count; index++)
             {
-                result.At(index, -At(index));
+                target.At(index, -At(index));
             }
-
-            return result;
         }
 
         /// <summary>