LA: fix a critical bug in SparseMatrix.Add when adding a matrix to itself #341

src/Numerics/LinearAlgebra/Complex/SparseMatrix.cs

@@ -726,7 +726,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                     CopyTo(result);
                 }
 
-                Control.LinearAlgebraProvider.ScaleArray(2.0, _storage.Values, _storage.Values);
+                Control.LinearAlgebraProvider.ScaleArray(2.0, sparseResult._storage.Values, sparseResult._storage.Values);
                 return;
             }
 

src/Numerics/LinearAlgebra/Complex32/SparseMatrix.cs

@@ -721,7 +721,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                     CopyTo(result);
                 }
 
-                Control.LinearAlgebraProvider.ScaleArray(2.0f, _storage.Values, _storage.Values);
+                Control.LinearAlgebraProvider.ScaleArray(2.0f, sparseResult._storage.Values, sparseResult._storage.Values);
                 return;
             }
 

src/Numerics/LinearAlgebra/Double/SparseMatrix.cs

@@ -721,7 +721,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                     CopyTo(result);
                 }
 
-                Control.LinearAlgebraProvider.ScaleArray(2.0, _storage.Values, _storage.Values);
+                Control.LinearAlgebraProvider.ScaleArray(2.0, sparseResult._storage.Values, sparseResult._storage.Values);
                 return;
             }
 

src/Numerics/LinearAlgebra/Single/SparseMatrix.cs

@@ -155,7 +155,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         {
             return OfColumnArrays(data.Select(v => v.ToArray()).ToArray());
         }
-        
+
         /// <summary>
         /// Create a new sparse matrix as a copy of the given enumerable of enumerable columns.
         /// Each enumerable in the master enumerable specifies a column.
@@ -725,7 +725,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                     CopyTo(result);
                 }
 
-                Control.LinearAlgebraProvider.ScaleArray(2.0f, _storage.Values, _storage.Values);
+                Control.LinearAlgebraProvider.ScaleArray(2.0f, sparseResult._storage.Values, sparseResult._storage.Values);
                 return;
             }
 
@@ -1095,7 +1095,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 for (var i = 0; i < RowCount; i++)
                 {
                     // Multiply row of matrix A on row of matrix B
- 
+
                     var startIndexThis = rowPointers[i];
                     var endIndexThis = rowPointers[i + 1];
 

src/UnitTests/LinearAlgebraTests/Complex/MatrixTests.Arithmetic.cs

@@ -251,6 +251,46 @@ namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Complex
             }
         }
 
+        /// <summary>
+        /// Can add a matrix.
+        /// </summary>
+        /// <param name="mtx">Matrix name.</param>
+        [TestCase("Square3x3")]
+        [TestCase("Tall3x2")]
+        public void CanAddMatrixToSelf(string mtx)
+        {
+            var matrix = TestMatrices[mtx].Clone();
+
+            var result = matrix.Add(matrix);
+            for (var i = 0; i < matrix.RowCount; i++)
+            {
+                for (var j = 0; j < matrix.ColumnCount; j++)
+                {
+                    Assert.AreEqual(result[i, j], 2*matrix[i, j]);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Can subtract a matrix.
+        /// </summary>
+        /// <param name="mtx">Matrix name.</param>
+        [TestCase("Square3x3")]
+        [TestCase("Tall3x2")]
+        public void CanSubtractMatrixFromSelf(string mtx)
+        {
+            var matrix = TestMatrices[mtx].Clone();
+
+            var result = matrix.Subtract(matrix);
+            for (var i = 0; i < matrix.RowCount; i++)
+            {
+                for (var j = 0; j < matrix.ColumnCount; j++)
+                {
+                    Assert.AreEqual(result[i, j], Complex.Zero);
+                }
+            }
+        }
+
         /// <summary>
         /// Adding a matrix with fewer columns throws <c>ArgumentOutOfRangeException</c>.
         /// </summary>

src/UnitTests/LinearAlgebraTests/Complex32/MatrixTests.Arithmetic.cs

@@ -247,6 +247,46 @@ namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Complex32
             }
         }
 
+        /// <summary>
+        /// Can add a matrix.
+        /// </summary>
+        /// <param name="mtx">Matrix name.</param>
+        [TestCase("Square3x3")]
+        [TestCase("Tall3x2")]
+        public void CanAddMatrixToSelf(string mtx)
+        {
+            var matrix = TestMatrices[mtx].Clone();
+
+            var result = matrix.Add(matrix);
+            for (var i = 0; i < matrix.RowCount; i++)
+            {
+                for (var j = 0; j < matrix.ColumnCount; j++)
+                {
+                    Assert.AreEqual(result[i, j], 2*matrix[i, j]);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Can subtract a matrix.
+        /// </summary>
+        /// <param name="mtx">Matrix name.</param>
+        [TestCase("Square3x3")]
+        [TestCase("Tall3x2")]
+        public void CanSubtractMatrixFromSelf(string mtx)
+        {
+            var matrix = TestMatrices[mtx].Clone();
+
+            var result = matrix.Subtract(matrix);
+            for (var i = 0; i < matrix.RowCount; i++)
+            {
+                for (var j = 0; j < matrix.ColumnCount; j++)
+                {
+                    Assert.AreEqual(result[i, j], Complex32.Zero);
+                }
+            }
+        }
+
         /// <summary>
         /// Adding a matrix with fewer columns throws <c>ArgumentOutOfRangeException</c>.
         /// </summary>

src/UnitTests/LinearAlgebraTests/Double/MatrixTests.Arithmetic.cs

@@ -27,7 +27,6 @@
 using System;
 using MathNet.Numerics.Distributions;
 using MathNet.Numerics.LinearAlgebra;
-using MathNet.Numerics.LinearAlgebra.Double;
 using NUnit.Framework;
 
 namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Double
@@ -241,6 +240,46 @@ namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Double
             }
         }
 
+        /// <summary>
+        /// Can add a matrix.
+        /// </summary>
+        /// <param name="mtx">Matrix name.</param>
+        [TestCase("Square3x3")]
+        [TestCase("Tall3x2")]
+        public void CanAddMatrixToSelf(string mtx)
+        {
+            var matrix = TestMatrices[mtx].Clone();
+
+            var result = matrix.Add(matrix);
+            for (var i = 0; i < matrix.RowCount; i++)
+            {
+                for (var j = 0; j < matrix.ColumnCount; j++)
+                {
+                    Assert.AreEqual(result[i, j], 2*matrix[i, j]);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Can subtract a matrix.
+        /// </summary>
+        /// <param name="mtx">Matrix name.</param>
+        [TestCase("Square3x3")]
+        [TestCase("Tall3x2")]
+        public void CanSubtractMatrixFromSelf(string mtx)
+        {
+            var matrix = TestMatrices[mtx].Clone();
+
+            var result = matrix.Subtract(matrix);
+            for (var i = 0; i < matrix.RowCount; i++)
+            {
+                for (var j = 0; j < matrix.ColumnCount; j++)
+                {
+                    Assert.AreEqual(result[i, j], 0d);
+                }
+            }
+        }
+
         /// <summary>
         /// Adding a matrix with fewer columns throws <c>ArgumentOutOfRangeException</c>.
         /// </summary>

src/UnitTests/LinearAlgebraTests/Single/MatrixTests.Arithmetic.cs

@@ -241,6 +241,46 @@ namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Single
             }
         }
 
+        /// <summary>
+        /// Can add a matrix.
+        /// </summary>
+        /// <param name="mtx">Matrix name.</param>
+        [TestCase("Square3x3")]
+        [TestCase("Tall3x2")]
+        public void CanAddMatrixToSelf(string mtx)
+        {
+            var matrix = TestMatrices[mtx].Clone();
+
+            var result = matrix.Add(matrix);
+            for (var i = 0; i < matrix.RowCount; i++)
+            {
+                for (var j = 0; j < matrix.ColumnCount; j++)
+                {
+                    Assert.AreEqual(result[i, j], 2*matrix[i, j]);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Can subtract a matrix.
+        /// </summary>
+        /// <param name="mtx">Matrix name.</param>
+        [TestCase("Square3x3")]
+        [TestCase("Tall3x2")]
+        public void CanSubtractMatrixFromSelf(string mtx)
+        {
+            var matrix = TestMatrices[mtx].Clone();
+
+            var result = matrix.Subtract(matrix);
+            for (var i = 0; i < matrix.RowCount; i++)
+            {
+                for (var j = 0; j < matrix.ColumnCount; j++)
+                {
+                    Assert.AreEqual(result[i, j], 0f);
+                }
+            }
+        }
+
         /// <summary>
         /// Adding a matrix with fewer columns throws <c>ArgumentOutOfRangeException</c>.
         /// </summary>