LA: Functional vector init

src/Numerics/LinearAlgebra/Complex/DenseVector.cs

@@ -126,17 +126,21 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         {
         }
 
+        /// <summary>
+        /// Create a new dense vector and initialize each value using the provided init function.
+        /// </summary>
+        public static DenseVector Create(int length, Func<int, Complex> init)
+        {
+            return new DenseVector(DenseVectorStorage<Complex>.OfInit(length, init));
+        }
+
         /// <summary>
         /// Create a new dense vector with values sampled from the provided random distribution.
         /// </summary>
-        public static DenseVector CreateRandom(int size, IContinuousDistribution distribution)
+        public static DenseVector CreateRandom(int length, IContinuousDistribution distribution)
         {
-            var storage = new DenseVectorStorage<Complex>(size);
-            for (var i = 0; i < storage.Data.Length; i++)
-            {
-                storage.Data[i] = new Complex(distribution.Sample(), distribution.Sample());
-            }
-            return new DenseVector(storage);
+            return new DenseVector(DenseVectorStorage<Complex>.OfInit(length,
+                i => new Complex(distribution.Sample(), distribution.Sample())));
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex/SparseVector.cs

@@ -127,6 +127,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         {
         }
 
+        /// <summary>
+        /// Create a new sparse vector and initialize each value using the provided init function.
+        /// </summary>
+        public static SparseVector Create(int length, Func<int, Complex> init)
+        {
+            return new SparseVector(SparseVectorStorage<Complex>.OfInit(length, init));
+        }
+
         /// <summary>
         /// Creates a matrix with the given dimensions using the same storage type
         /// as this vector.

src/Numerics/LinearAlgebra/Complex32/DenseVector.cs

@@ -126,17 +126,21 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         {
         }
 
+        /// <summary>
+        /// Create a new dense vector and initialize each value using the provided init function.
+        /// </summary>
+        public static DenseVector Create(int length, Func<int, Complex32> init)
+        {
+            return new DenseVector(DenseVectorStorage<Complex32>.OfInit(length, init));
+        }
+
         /// <summary>
         /// Create a new dense vector with values sampled from the provided random distribution.
         /// </summary>
-        public static DenseVector CreateRandom(int size, IContinuousDistribution distribution)
+        public static DenseVector CreateRandom(int length, IContinuousDistribution distribution)
         {
-            var storage = new DenseVectorStorage<Complex32>(size);
-            for (var i = 0; i < storage.Data.Length; i++)
-            {
-                storage.Data[i] = new Complex32((float)distribution.Sample(), (float)distribution.Sample());
-            }
-            return new DenseVector(storage);
+            return new DenseVector(DenseVectorStorage<Complex32>.OfInit(length,
+                i => new Complex32((float) distribution.Sample(), (float) distribution.Sample())));
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex32/SparseVector.cs

@@ -127,6 +127,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         {
         }
 
+        /// <summary>
+        /// Create a new sparse vector and initialize each value using the provided init function.
+        /// </summary>
+        public static SparseVector Create(int length, Func<int, Complex32> init)
+        {
+            return new SparseVector(SparseVectorStorage<Complex32>.OfInit(length, init));
+        }
+
         /// <summary>
         /// Creates a matrix with the given dimensions using the same storage type
         /// as this vector.

src/Numerics/LinearAlgebra/Double/DenseVector.cs

@@ -127,17 +127,21 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         {
         }
 
+        /// <summary>
+        /// Create a new dense vector and initialize each value using the provided init function.
+        /// </summary>
+        public static DenseVector Create(int length, Func<int, double> init)
+        {
+            return new DenseVector(DenseVectorStorage<double>.OfInit(length, init));
+        }
+
         /// <summary>
         /// Create a new dense vector with values sampled from the provided random distribution.
         /// </summary>
-        public static DenseVector CreateRandom(int size, IContinuousDistribution distribution)
+        public static DenseVector CreateRandom(int length, IContinuousDistribution distribution)
         {
-            var storage = new DenseVectorStorage<double>(size);
-            for (var i = 0; i < storage.Data.Length; i++)
-            {
-                storage.Data[i] = distribution.Sample();
-            }
-            return new DenseVector(storage);
+            return new DenseVector(DenseVectorStorage<double>.OfInit(length,
+                i => distribution.Sample()));
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Double/SparseVector.cs

@@ -127,6 +127,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         {
         }
 
+        /// <summary>
+        /// Create a new sparse vector and initialize each value using the provided init function.
+        /// </summary>
+        public static SparseVector Create(int length, Func<int, double> init)
+        {
+            return new SparseVector(SparseVectorStorage<double>.OfInit(length, init));
+        }
+
         /// <summary>
         /// Creates a matrix with the given dimensions using the same storage type
         /// as this vector.

src/Numerics/LinearAlgebra/Single/DenseVector.cs

@@ -126,17 +126,21 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         {
         }
 
+        /// <summary>
+        /// Create a new dense vector and initialize each value using the provided init function.
+        /// </summary>
+        public static DenseVector Create(int length, Func<int, float> init)
+        {
+            return new DenseVector(DenseVectorStorage<float>.OfInit(length, init));
+        }
+
         /// <summary>
         /// Create a new dense vector with values sampled from the provided random distribution.
         /// </summary>
-        public static DenseVector CreateRandom(int size, IContinuousDistribution distribution)
+        public static DenseVector CreateRandom(int length, IContinuousDistribution distribution)
         {
-            var storage = new DenseVectorStorage<float>(size);
-            for (var i = 0; i < storage.Data.Length; i++)
-            {
-                storage.Data[i] = (float)distribution.Sample();
-            }
-            return new DenseVector(storage);
+            return new DenseVector(DenseVectorStorage<float>.OfInit(length,
+                i => (float) distribution.Sample()));
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Single/SparseVector.cs

@@ -127,6 +127,14 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         {
         }
 
+        /// <summary>
+        /// Create a new sparse vector and initialize each value using the provided init function.
+        /// </summary>
+        public static SparseVector Create(int length, Func<int, float> init)
+        {
+            return new SparseVector(SparseVectorStorage<float>.OfInit(length, init));
+        }
+
         /// <summary>
         /// Creates a matrix with the given dimensions using the same storage type
         /// as this vector.

src/Numerics/LinearAlgebra/Storage/DenseVectorStorage.cs

@@ -99,6 +99,21 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return storage;
         }
 
+        public static DenseVectorStorage<T> OfInit(int length, Func<int, T> init)
+        {
+            if (length < 1)
+            {
+                throw new ArgumentOutOfRangeException("length", string.Format(Resources.ArgumentLessThanOne, length));
+            }
+
+            var data = new T[length];
+            for (int i = 0; i < data.Length; i++)
+            {
+                data[i] = init(i);
+            }
+            return new DenseVectorStorage<T>(length, data);
+        }
+
         public static DenseVectorStorage<T> OfEnumerable(IEnumerable<T> data)
         {
             if (data == null)

src/Numerics/LinearAlgebra/Storage/SparseVectorStorage.cs

@@ -291,6 +291,32 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
             return storage;
         }
 
+        public static SparseVectorStorage<T> OfInit(int length, Func<int, T> init)
+        {
+            if (length < 1)
+            {
+                throw new ArgumentOutOfRangeException("length", string.Format(Resources.ArgumentLessThanOne, length));
+            }
+
+            var indices = new List<int>();
+            var values = new List<T>();
+            for (int i = 0; i < length; i++)
+            {
+                var item = init(i);
+                if (!Zero.Equals(item))
+                {
+                    values.Add(item);
+                    indices.Add(length);
+                }
+            }
+            return new SparseVectorStorage<T>(length)
+                {
+                    Indices = indices.ToArray(),
+                    Values = values.ToArray(),
+                    ValueCount = values.Count
+                };
+        }
+
         public static SparseVectorStorage<T> OfEnumerable(IEnumerable<T> data)
         {
             if (data == null)