#531 Fix the monolithic Stokes (that failed due to my temporary assumption in...

#531 Fix the monolithic Stokes (that failed due to my temporary assumption in the computation of the local matrix to inject into the global one).

Sources/FiniteElement/Operators/GlobalVariationalOperator/Private/Impl/Recursivity.hxx

@@ -155,10 +155,28 @@ namespace HappyHeart
             {
                 const auto& elementary_data = local_variational_operator.GetElementaryData();
                 
+                // #197 const_cast to remove! Very ugly, but I guarantee the underlying value is not modified...
+                auto& local_matrix = const_cast<LocalMatrix&>(elementary_data.GetMatrixResult());
+                
+                
                 const auto& unknown_and_numbering_subset_list =
                     local_variational_operator.GetUnknownAndNumberingSubsetList();
                 
+                if (row_numbering_subset == col_numbering_subset
+                    && std::all_of(unknown_and_numbering_subset_list.cbegin(),
+                                   unknown_and_numbering_subset_list.cend(),
+                                   [&row_numbering_subset](const auto& item_ptr)
+                                   {
+                                       assert(!(!item_ptr));
+                                       return item_ptr->GetNumberingSubset() == row_numbering_subset;
+                                   }))
+                {
+                    // Monolithic case; we can return directly the whole matrix.
+                    return local_matrix;
+                }
 
+                
+                
                 Unknown::vector_const_shared_ptr row_unknown_list;
                 Unknown::vector_const_shared_ptr col_unknown_list;
                 
@@ -184,9 +202,7 @@ namespace HappyHeart
 //                assert(it != reduced_local_matrix_.cend());
 //                `auto& ret = it->second;
                 
-                // #197 const_cast to remove! Very ugly, but I guarantee the underlying value is not modified...
-                auto& local_matrix = const_cast<LocalMatrix&>(elementary_data.GetMatrixResult());
-            
+                
                 auto block = elementary_data.ExtractBlockFromLocalMatrix(elementary_data.GetRefFElt(unknown1),
                                                                          elementary_data.GetRefFElt(unknown2),
                                                                          local_matrix);