On Tue, Jan 31, 2023 at 2:38 AM Shiyue Li <shiyue...@brown.edu> wrote: > > Hi all, > > I am hoping to generate a list of all graph isomorphism classes of a given > size. The current code that I have first generate all the graphs on 2n, and > then take all the isomorphism class representatives of size n. But the first > step of generating all graphs on 2n vertices can take a really long time and > huge amount of memory (run 10 days on my university's research computing > cloud) and crashes. > > See the following for my code: > > def iso_graphs(n): > '''returns all isomorphism classes of simple graphs on n edges on 2*n > vertices''' > L = list(graphs(2 * n, loops=False, size=n)) print("Do we ever reach this > point?") > L = [G.canonical_label().copy(immutable=True) for G in L if G.size() == n] > return L > > I wonder if what is a correct and efficient way of doing it.
We have a function to do this job very efficently: graphs.nauty_geng() it generates non-isomorphic graphs. E.g. list(graphs.nauty_geng("3 -c")) gives you the complete list (of lengh 2) of all non-isomrphic connected graphs on 3 vertices (remove "-c" there if you want all graphs, not only connected) HTH Dima > > Thanks! > > -- > You received this message because you are subscribed to the Google Groups > "sage-support" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-support+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-support/0acb6537-3fe9-42dc-ab1b-c5c79dd5fb5cn%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/CAAWYfq0EG%2BGhzJu%3D6iw%3DHmxe%2Bfwbd3%2BAEVdd%2BWtPnq_DO_8Bsg%40mail.gmail.com.