add missing method mtv (mv and umtv exist, so mtv should exist, too)

[[Imported from SVN: r5532]]

common/fmatrix.hh

@@ -304,6 +304,25 @@ namespace Dune {
       }
     }
 
+    //! y = A^T x
+    template< class X, class Y >
+    void mtv ( const X &x, Y &y ) const
+    {
+#ifdef DUNE_FMatrix_WITH_CHECKING
+      assert( &x != &y );
+      if( x.N() != N() )
+        DUNE_THROW( FMatrixError, "Index out of range." );
+      if( y.N() != M() )
+        DUNE_THROW( FMatrixError, "Index out of range." );
+#endif
+      for( size_type i = 0; i < m; ++i )
+      {
+        y[ i ] = 0;
+        for( size_type j = 0; j < n; ++j )
+          y[ i ] += (*this)[ j ][ i ] * x[ j ];
+      }
+    }
+
     //! y += A x
     template<class X, class Y>
     void umv (const X& x, Y& y) const