Previous commits were for DenseMatrix. Created stubs for SparseMatrix.

src/Numerics/LinearAlgebra/Double/SparseMatrix.cs

@@ -1444,6 +1444,26 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             }
         }
 
+        /// <summary>
+        /// Multiplies the transpose of this matrix with a vector and places the results into the result vector.
+        /// </summary>
+        /// <param name="rightSide">The vector to multiply with.</param>
+        /// <param name="result">The result of the multiplication.</param>
+        protected override void DoTransposeThisAndMultiply(Vector<double> rightSide, Vector<double> result)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// Multiplies the transpose of this matrix with another matrix and places the results into the result matrix.
+        /// </summary>
+        /// <param name="other">The matrix to multiply with.</param>
+        /// <param name="result">The result of the multiplication.</param>
+        protected override void DoTransposeThisAndMultiply(Matrix<double> other, Matrix<double> result)
+        {
+            throw new NotImplementedException();
+        }
+
         /// <summary>
         /// Negate each element of this matrix and place the results into the result matrix.
         /// </summary>