Sorry I should make it clearer. I’m using graphviz library in Python, so I create an graphviz.Diagraph object called dot, and eventually I rendered it to be a pdf file. Currently the difference in time it takes with/without plotting is huge: 3 min without plot, over 1 hour with plot. And since the parameters such as nslimit and maxiter are related to the number of iterations, I’d like to know is it because of from dotfile(xxx.gv)->pdf takes much time or somewhere else.