[cleanup] Implement MultiTypeBlock* assignment using Hybrid::forEach

The implementation in MultiTypeBlockMatrix would be even
simpler, if it would provide a static size() method, because
we could then use a simple Hybrid::forEach over its entries
instead of one over all indices.

dune/istl/multitypeblockmatrix.hh

@@ -7,6 +7,8 @@
 #include <iostream>
 #include <tuple>
 
+#include <dune/common/hybridutilities.hh>
+
 #include "istlexception.hh"
 
 // forward declaration
@@ -69,45 +71,6 @@ namespace Dune {
 
 
 
-  //make MultiTypeBlockVector_Ident known (for MultiTypeBlockMatrix_Ident)
-  template<int count, typename T1, typename T2>
-  class MultiTypeBlockVector_Ident;
-
-
-  /**
-     @brief Set a MultiTypeBlockMatrix to some specific scalar value
-
-     This class is used by the MultiTypeBlockMatrix class' internal assignment operator.
-     Whenever a vector is assigned a scalar value, each block element
-     has to provide operator= for the right side. Example:
-     \code
-     typedef MultiTypeBlockVector<int,int,int> CVect;
-     MultiTypeBlockMatrix<CVect,CVect> CMat;
-     CMat = 3;                   //sets all 3x2 integer elements to 3
-     \endcode
-   */
-  template<int rowcount, typename T1, typename T2>
-  class MultiTypeBlockMatrix_Ident {
-  public:
-
-    /**
-     * equalize two matrix' element
-     * note: uses MultiTypeBlockVector_Ident to equalize each row (which is of MultiTypeBlockVector type)
-     */
-    static void equalize(T1& a, const T2& b) {
-      MultiTypeBlockVector_Ident<T1::M(),T1,T2>::equalize(a,b);              //rows are cvectors
-      MultiTypeBlockMatrix_Ident<rowcount-1,T1,T2>::equalize(a,b);         //iterate over rows
-    }
-  };
-
-  //recursion end for rowcount=0
-  template<typename T1, typename T2>
-  class MultiTypeBlockMatrix_Ident<0,T1,T2> {
-  public:
-    static void equalize (T1&, const T2&)
-    {}
-  };
-
   /**
      @brief Matrix-vector multiplication
 
@@ -259,7 +222,16 @@ namespace Dune {
      * assignment operator
      */
     template<typename T>
-    void operator= (const T& newval) {MultiTypeBlockMatrix_Ident<N(),type,T>::equalize(*this, newval); }
+    void operator= (const T& newval) {
+      using namespace Dune::Hybrid;
+      auto size = index_constant<1+sizeof...(Args)>();
+      // Since Dune::Hybrid::size(MultiTypeBlockMatrix) is not implemented,
+      // we cannot use a plain forEach(*this, ...). This could be achived,
+      // e.g., by implementing a static size() method.
+      forEach(integralRange(size), [&](auto&& i) {
+        (*this)[i] = newval;
+      });
+    }
 
     /** \brief y = A x
      */

dune/istl/multitypeblockvector.hh

@@ -9,6 +9,7 @@
 
 #include <dune/common/dotproduct.hh>
 #include <dune/common/ftraits.hh>
+#include <dune/common/hybridutilities.hh>
 
 #include "istlexception.hh"
 
@@ -64,38 +65,6 @@ namespace Dune {
 
 
 
-  /**
-     @brief Set a MultiTypeBlockVector to some specific value
-
-     This class is used by the MultiTypeBlockVector class' internal = operator.
-     Whenever a vector is assigned to a value, each vector element
-     has to provide the = operator for the right side. Example:
-     \code
-     MultiTypeBlockVector<int,int,int> CVect;
-     CVect = 3;                  //sets all integer elements to 3
-     \endcode
-   */
-  template<int count, typename T1, typename T2>
-  class MultiTypeBlockVector_Ident {
-  public:
-
-    /**
-     * equalize two vectors' element (index is template parameter count)
-     * note: each MultiTypeBlockVector element has to provide the = operator with type T2
-     */
-    static void equalize(T1& a, const T2& b) {
-      std::get<count-1>(a) = b;           //equalize current elements
-      MultiTypeBlockVector_Ident<count-1,T1,T2>::equalize(a,b);    //next elements
-    }
-  };
-  template<typename T1, typename T2>                      //recursion end (count=0)
-  class MultiTypeBlockVector_Ident<0,T1,T2> {public: static void equalize (T1&, const T2&) {} };
-
-
-
-
-
-
   /**
      @brief Add/subtract second vector to/from the first (v1 += v2)
 
@@ -386,7 +355,11 @@ namespace Dune {
     /** \brief Assignment operator
      */
     template<typename T>
-    void operator= (const T& newval) {MultiTypeBlockVector_Ident<sizeof...(Args),type,T>::equalize(*this, newval); }
+    void operator= (const T& newval) {
+      Dune::Hybrid::forEach(*this, [&](auto&& entry) {
+        entry = newval;
+      });
+    }
 
     /**
      * operator for MultiTypeBlockVector += MultiTypeBlockVector operations