Add SymmetricMatrixStorage

Signed-off-by: Alexander Karatarakis <alex@karatarakis.com>

src/Numerics/LinearAlgebra/Storage/DenseColumnMajorSymmetricMatrixStorage.cs

@@ -5,7 +5,7 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
     using MathNet.Numerics.LinearAlgebra.Storage.Indexers.Static;
     using MathNet.Numerics.Properties;
 
-    public class DenseColumnMajorSymmetricMatrixStorage<T> : MatrixStorage<T>
+    public class DenseColumnMajorSymmetricMatrixStorage<T> : SymmetricMatrixStorage<T>
         where T : struct, IEquatable<T>, IFormattable
     {
         // [ruegg] public fields are OK here
@@ -15,14 +15,14 @@ namespace MathNet.Numerics.LinearAlgebra.Storage
         public readonly PackedStorageIndexerUpper Indexer;
 
         internal DenseColumnMajorSymmetricMatrixStorage(int order)
-            : base(order, order)
+            : base(order)
         {
             Indexer = new PackedStorageIndexerUpper(order);
             Data = new T[Indexer.DataLength];
         }
 
         internal DenseColumnMajorSymmetricMatrixStorage(int order, T[] data)
-            : base(order, order)
+            : base(order)
         {
             if (data == null)
             {

src/Numerics/LinearAlgebra/Storage/SymmetricMatrixStorage.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace MathNet.Numerics.LinearAlgebra.Storage
+{
+    using MathNet.Numerics.Properties;
+
+    public abstract class SymmetricMatrixStorage<T> : MatrixStorage<T> 
+        where T : struct, IEquatable<T>, IFormattable
+    {
+        // [ruegg] public fields are OK here
+
+        protected SymmetricMatrixStorage(int order)
+         : base(order, order)
+        {
+        }
+
+        public override bool IsFullyMutable
+        {
+            get { return false; }
+        }
+
+        public override bool IsMutable(int row, int column)
+        {
+            return row <= column;
+        }
+
+        public override void Clear()
+        {
+            for (var i = 0; i < RowCount; i++)
+            {
+                for (var j = i; j < ColumnCount; j++)
+                {
+                    At(i, j, default(T));
+                }
+            }
+        }
+         
+        public override void Clear(int rowIndex, int rowCount, int columnIndex, int columnCount)
+        {
+            for (var i = rowIndex; i < rowIndex + rowCount; i++)
+            {
+                for (var j = Math.Max(columnIndex, i); j < columnIndex + columnCount; j++)
+                {
+                    At(i, j, default(T));
+                }
+            }
+        }
+    }
+}

src/Numerics/Numerics.csproj

@@ -359,6 +359,7 @@
     <Compile Include="LinearAlgebra\Storage\MatrixStorage.cs" />
     <Compile Include="LinearAlgebra\Storage\SparseCompressedRowMatrixStorage.cs" />
     <Compile Include="LinearAlgebra\Storage\DiagonalMatrixStorage.cs" />
+    <Compile Include="LinearAlgebra\Storage\SymmetricMatrixStorage.cs" />
     <Compile Include="LinearAlgebra\Storage\VectorStorage.cs" />
     <Compile Include="LinearAlgebra\Storage\VectorStorage.Validation.cs" />
     <Compile Include="Permutation.cs" />