added new constructor to sparse matrix that takes a matrix. Replaced new SparseMatrix(matrix.ToArray()) calls with it

src/Numerics/LinearAlgebra/Complex/Solvers/Preconditioners/Ilutp.cs

@@ -316,7 +316,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers.Preconditioners
                 throw new ArgumentException(Resources.ArgumentMatrixSquare, "matrix");
             }
 
-            var sparseMatrix = (matrix is SparseMatrix) ? matrix as SparseMatrix : new SparseMatrix(matrix.ToArray());
+            var sparseMatrix = (matrix is SparseMatrix) ? matrix as SparseMatrix : new SparseMatrix(matrix);
 
             // The creation of the preconditioner follows the following algorithm.
             // spaceLeft = lfilNnz * nnz(A)

src/Numerics/LinearAlgebra/Complex/Solvers/Preconditioners/IncompleteLU.cs

@@ -114,7 +114,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Solvers.Preconditioners
                 throw new ArgumentException(Resources.ArgumentMatrixSquare, "matrix");
             }
 
-            _decompositionLU = new SparseMatrix(matrix.ToArray());
+            _decompositionLU = new SparseMatrix(matrix);
 
             // M == A
             // for i = 2, ... , n do

src/Numerics/LinearAlgebra/Complex/SparseMatrix.cs

@@ -188,6 +188,42 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
             }
         }
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SparseMatrix"/> class, copying
+        /// the values from the given matrix.
+        /// </summary>
+        /// <param name="matrix">The matrix to copy.</param>
+        public SparseMatrix(Matrix<Complex> matrix)
+            : base(matrix.RowCount, matrix.ColumnCount)
+        {
+            var sparseMatrix = matrix as SparseMatrix;
+
+            var rows = matrix.RowCount;
+            var columns = matrix.ColumnCount;
+
+            if (sparseMatrix == null)
+            {
+                for (var i = 0; i < rows; i++)
+                {
+                    for (var j = 0; j < columns; j++)
+                    {
+                        SetValueAt(i, j, matrix.At(i, j));
+                    }
+                }
+            }
+            else
+            {
+                NonZerosCount = sparseMatrix.NonZerosCount;
+                _rowIndex = new int[rows];
+                _columnIndices = new int[NonZerosCount];
+                _nonZeroValues = new Complex[NonZerosCount];
+
+                Array.Copy(sparseMatrix._nonZeroValues, _nonZeroValues, NonZerosCount);
+                Array.Copy(sparseMatrix._columnIndices, _columnIndices, NonZerosCount);
+                Array.Copy(sparseMatrix._rowIndex, _rowIndex, rows);
+            }
+        }
+
         /// <summary>
         /// Creates a <c>SparseMatrix</c> for the given number of rows and columns.
         /// </summary>

src/Numerics/LinearAlgebra/Complex32/Solvers/Preconditioners/Ilutp.cs

@@ -316,7 +316,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers.Preconditioners
                 throw new ArgumentException(Resources.ArgumentMatrixSquare, "matrix");
             }
 
-            var sparseMatrix = (matrix is SparseMatrix) ? matrix as SparseMatrix : new SparseMatrix(matrix.ToArray());
+            var sparseMatrix = (matrix is SparseMatrix) ? matrix as SparseMatrix : new SparseMatrix(matrix);
 
             // The creation of the preconditioner follows the following algorithm.
             // spaceLeft = lfilNnz * nnz(A)

src/Numerics/LinearAlgebra/Complex32/Solvers/Preconditioners/IncompleteLU.cs

@@ -114,7 +114,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Solvers.Preconditioners
                 throw new ArgumentException(Resources.ArgumentMatrixSquare, "matrix");
             }
 
-            _decompositionLU = new SparseMatrix(matrix.ToArray());
+            _decompositionLU = new SparseMatrix(matrix);
 
             // M == A
             // for i = 2, ... , n do

src/Numerics/LinearAlgebra/Complex32/SparseMatrix.cs

@@ -183,6 +183,42 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
             }
         }
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SparseMatrix"/> class, copying
+        /// the values from the given matrix.
+        /// </summary>
+        /// <param name="matrix">The matrix  to copy.</param>
+        public SparseMatrix(Matrix<Complex32> matrix)
+            : base(matrix.RowCount, matrix.ColumnCount)
+        {
+            var sparseMatrix = matrix as SparseMatrix;
+
+            var rows = matrix.RowCount;
+            var columns = matrix.ColumnCount;
+
+            if (sparseMatrix == null)
+            {
+                for (var i = 0; i < rows; i++)
+                {
+                    for (var j = 0; j < columns; j++)
+                    {
+                        SetValueAt(i, j, matrix.At(i, j));
+                    }
+                }
+            }
+            else
+            {
+                NonZerosCount = sparseMatrix.NonZerosCount;
+                _rowIndex = new int[rows];
+                _columnIndices = new int[NonZerosCount];
+                _nonZeroValues = new Complex32[NonZerosCount];
+
+                Array.Copy(sparseMatrix._nonZeroValues, _nonZeroValues, NonZerosCount);
+                Array.Copy(sparseMatrix._columnIndices, _columnIndices, NonZerosCount);
+                Array.Copy(sparseMatrix._rowIndex, _rowIndex, rows);
+            }
+        }
+
         /// <summary>
         /// Creates a <c>SparseMatrix</c> for the given number of rows and columns.
         /// </summary>

src/Numerics/LinearAlgebra/Double/Solvers/Preconditioners/Ilutp.cs

@@ -315,7 +315,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers.Preconditioners
                 throw new ArgumentException(Resources.ArgumentMatrixSquare, "matrix");
             }
 
-            var sparseMatrix = (matrix is SparseMatrix) ? matrix as SparseMatrix : new SparseMatrix(matrix.ToArray());
+            var sparseMatrix = (matrix is SparseMatrix) ? matrix as SparseMatrix : new SparseMatrix(matrix);
 
             // The creation of the preconditioner follows the following algorithm.
             // spaceLeft = lfilNnz * nnz(A)

src/Numerics/LinearAlgebra/Double/Solvers/Preconditioners/IncompleteLU.cs

@@ -113,7 +113,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Solvers.Preconditioners
                 throw new ArgumentException(Resources.ArgumentMatrixSquare, "matrix");
             }
 
-            _decompositionLU = new SparseMatrix(matrix.ToArray());
+            _decompositionLU = new SparseMatrix(matrix);
 
             // M == A
             // for i = 2, ... , n do

src/Numerics/LinearAlgebra/Double/SparseMatrix.cs

@@ -182,6 +182,41 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             }
         }
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SparseMatrix"/> class, copying
+        /// the values from the given matrix.
+        /// </summary>
+        /// <param name="matrix">The matrix to copy.</param>
+        public SparseMatrix(Matrix<double> matrix) : base(matrix.RowCount, matrix.ColumnCount)
+        {
+            var sparseMatrix = matrix as SparseMatrix;
+
+            var rows = matrix.RowCount;
+            var columns = matrix.ColumnCount;
+
+            if (sparseMatrix == null)
+            {
+                for (var i = 0; i < rows; i++)
+                {
+                    for (var j = 0; j < columns; j++)
+                    {
+                        SetValueAt(i, j, matrix.At(i, j));
+                    }
+                }  
+            }
+            else
+            {
+                NonZerosCount = sparseMatrix.NonZerosCount;
+                _rowIndex = new int[rows];
+                _columnIndices = new int[NonZerosCount];
+                _nonZeroValues = new double[NonZerosCount];
+
+                Buffer.BlockCopy(sparseMatrix._nonZeroValues, 0, _nonZeroValues, 0, NonZerosCount * Constants.SizeOfDouble);
+                Buffer.BlockCopy(sparseMatrix._columnIndices, 0, _columnIndices, 0, NonZerosCount * Constants.SizeOfInt);
+                Buffer.BlockCopy(sparseMatrix._rowIndex, 0, _rowIndex, 0, rows * Constants.SizeOfInt);
+            }
+        }
+
         /// <summary>
         /// Creates a <c>SparseMatrix</c> for the given number of rows and columns.
         /// </summary>

src/Numerics/LinearAlgebra/Single/Solvers/Preconditioners/Ilutp.cs

@@ -315,7 +315,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers.Preconditioners
                 throw new ArgumentException(Resources.ArgumentMatrixSquare, "matrix");
             }
 
-            var sparseMatrix = (matrix is SparseMatrix) ? matrix as SparseMatrix : new SparseMatrix(matrix.ToArray());
+            var sparseMatrix = (matrix is SparseMatrix) ? matrix as SparseMatrix : new SparseMatrix(matrix);
 
             // The creation of the preconditioner follows the following algorithm.
             // spaceLeft = lfilNnz * nnz(A)

src/Numerics/LinearAlgebra/Single/Solvers/Preconditioners/IncompleteLU.cs

@@ -113,7 +113,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Solvers.Preconditioners
                 throw new ArgumentException(Resources.ArgumentMatrixSquare, "matrix");
             }
 
-            _decompositionLU = new SparseMatrix(matrix.ToArray());
+            _decompositionLU = new SparseMatrix(matrix);
 
             // M == A
             // for i = 2, ... , n do

src/Numerics/LinearAlgebra/Single/SparseMatrix.cs

@@ -182,6 +182,42 @@ namespace MathNet.Numerics.LinearAlgebra.Single
             }
         }
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SparseMatrix"/> class, copying
+        /// the values from the given matrix.
+        /// </summary>
+        /// <param name="matrix">The matrix to copy.</param>
+        public SparseMatrix(Matrix<float> matrix)
+            : base(matrix.RowCount, matrix.ColumnCount)
+        {
+            var sparseMatrix = matrix as SparseMatrix;
+
+            var rows = matrix.RowCount;
+            var columns = matrix.ColumnCount;
+
+            if (sparseMatrix == null)
+            {
+                for (var i = 0; i < rows; i++)
+                {
+                    for (var j = 0; j < columns; j++)
+                    {
+                        SetValueAt(i, j, matrix.At(i, j));
+                    }
+                }
+            }
+            else
+            {
+                NonZerosCount = sparseMatrix.NonZerosCount;
+                _rowIndex = new int[rows];
+                _columnIndices = new int[NonZerosCount];
+                _nonZeroValues = new float[NonZerosCount];
+
+                Buffer.BlockCopy(sparseMatrix._nonZeroValues, 0, _nonZeroValues, 0, NonZerosCount * Constants.SizeOfFloat);
+                Buffer.BlockCopy(sparseMatrix._columnIndices, 0, _columnIndices, 0, NonZerosCount * Constants.SizeOfInt);
+                Buffer.BlockCopy(sparseMatrix._rowIndex, 0, _rowIndex, 0, rows * Constants.SizeOfInt);
+            }
+        }
+
         /// <summary>
         /// Creates a <c>SparseMatrix</c> for the given number of rows and columns.
         /// </summary>