use iterators to get index in trace

experimental/include/scalfmm/tree/group_tree.hpp

@@ -500,10 +500,11 @@ namespace scalfmm::component
                           std::cout << "       " << leaf.index() << "  p2p_list (" << leaf_symbolics.number_of_neighbors
                                     << "): ";
                           // get the p2p interacion list
-                          auto index = leaf_symbolics.interaction_indexes;
-                          for(int idx = 0; idx < leaf_symbolics.number_of_neighbors; ++idx)
+                          // auto index = leaf_symbolics.interaction_indexes;
+                          auto index = leaf_symbolics.interaction_iterators;
+                          for(int idx = 0; idx < leaf_symbolics.existing_neighbors_in_group; ++idx)
                           {
-                              std::cout << index[idx] << " ";
+                              std::cout << index[idx]->index() << " ";
                           }
                           std::cout << std::endl;
                       });
@@ -534,12 +535,12 @@ namespace scalfmm::component
                         component::for_each(std::begin(*ptr_group), std::end(*ptr_group), [](auto& cell) {
                             auto& cell_symbolics = cell.symbolics();
                             std::cout << "       " << cell.index() << "  m2l_list ("
-                                      << cell_symbolics.number_of_neighbors << "): ";
+                                      << cell_symbolics.existing_neighbors << "): ";
                             // get the m2l interacion list
-                            auto index = cell_symbolics.interaction_indexes;
-                            for(int idx = 0; idx < cell_symbolics.number_of_neighbors; ++idx)
+                            auto index = cell_symbolics.interaction_iterators;
+                            for(int idx = 0; idx < cell_symbolics.existing_neighbors; ++idx)
                             {
-                                std::cout << index[idx] << " ";
+                                std::cout << index[idx]->index() << " ";
                             }
                             std::cout << std::endl;
                         });