+ if((e->origin_vertex->last_change < 0 && e->terminal_vertex->last_change >= 0) ||
+ (e->origin_vertex->last_change >= 0 && e->terminal_vertex->last_change < 0)) {
+ cout << "Inconsistent non-connexity (this should never happen)." << endl;
+ abort();
+ }
+ if(e->origin_vertex->last_change >= 0 &&
+ e->terminal_vertex->last_change >= 0 &&
+ e->positivized_length < 0) {