[Matrix]

use FieldTraits to determin the return type of the norm methods

dune/istl/matrix.hh

@@ -11,6 +11,7 @@
 #include <memory>
 
 #include <dune/istl/vbvector.hh>
+#include <dune/common/ftraits.hh>
 
 namespace Dune {
 
@@ -485,13 +486,13 @@ namespace Dune {
     //===== norms
 
     //! frobenius norm: sqrt(sum over squared values of entries)
-    double frobenius_norm () const
+    typename FieldTraits<field_type>::real_type frobenius_norm () const
     {
       return std::sqrt(frobenius_norm2());
     }
 
     //! square of frobenius norm, need for block recursion
-    double frobenius_norm2 () const
+    typename FieldTraits<field_type>::real_type frobenius_norm2 () const
     {
       double sum=0;
       for (size_type i=0; i<N(); ++i)
@@ -501,7 +502,7 @@ namespace Dune {
     }
 
     //! infinity norm (row sum norm, how to generalize for blocks?)
-    double infinity_norm () const
+    typename FieldTraits<field_type>::real_type infinity_norm () const
     {
       double max=0;
       for (size_type i=0; i<N(); ++i) {
@@ -514,7 +515,7 @@ namespace Dune {
     }
 
     //! simplified infinity norm (uses Manhattan norm for complex values)
-    double infinity_norm_real () const
+    typename FieldTraits<field_type>::real_type infinity_norm_real () const
     {
       double max=0;
       for (size_type i=0; i<N(); ++i) {