add operator+= to transposed view

src/amdis/common/Transposed.hpp

@@ -65,6 +65,18 @@ namespace AMDiS
       return matrix_.N();
     }
 
+    template <class Mat>
+    TransposedMatrix& operator+=(Mat const& mat)
+    {
+      assert(mat.N() == N());
+      assert(mat.M() == M());
+      for (size_type i = 0; i < N(); ++i)
+        for (size_type j = 0; j < M(); ++j)
+          (*this)[i][j] += mat[i][j];
+
+      return *this;
+    }
+
   private:
     Matrix& matrix_;
   };