[DenseMatrix] Use default implementation DenseMatrixAssigner in assignment from primitive types

The default implementation of DenseMatrixAssigner replaces redundant
code in dense matrix constructors taking a primitive data type.

dune/common/densematrix.hh

@@ -61,6 +61,8 @@ namespace Dune
      representing a field and a compile-time given number of rows and columns.
    */
 
+
+
   /**
      \brief you have to specialize this structure for any type that should be assignable to a DenseMatrix
      \tparam DenseMatrix Some type implementing the dense matrix interface
@@ -71,6 +73,16 @@ namespace Dune
 
 
 
+  template< class DenseMatrix, class K, int N, int M >
+  void istl_assign_to_fmatrix ( DenseMatrix &denseMatrix, const K (&values)[ M ][ N ] )
+  {
+    for( int i = 0; i < N; ++i )
+      for( int j = 0; j < M; ++j )
+        denseMatrix[ i ][ j ] = values[ i ][ j ];
+  }
+
+
+
 #ifndef DOXYGEN
   namespace
   {
@@ -134,7 +146,7 @@ namespace Dune
       {
         static void apply ( M &m, const T &t )
         {
-          static_assert( Conversion< T, typename DenseMatrix::field_type >::exists, "No specialization found" );
+          static_assert( Conversion< T, M >::exists, "No specialization found" );
           m = static_cast< const M & >( t );
         }
       };

dune/common/fmatrix.hh

@@ -90,11 +90,6 @@ namespace Dune
 
     /** \brief Constructor initializing the whole matrix with a scalar
      */
-    explicit FieldMatrix ( typename Base::field_type value )
-    {
-      _data.fill( row_type( value ) );
-    }
-
     template< class Other >
     FieldMatrix ( const Other &other )
     {