+ my $label = $showg->get_edge_attribute($ca,$cb,'label');
+ $label .= "\ndropped - weakest in iter.$dropiter";
+ $showg->set_edge_attribute($ca,$cb,'label',$label);
+ $showg->set_edge_attribute($ca,$cb,'style','dotted');
+ $showg->set_edge_attribute($ca,$cb,'graphviz',{constraint=>0});