Hello ! > How can that be? Isn't generally the test by "==" first checking whether > the two arguments are identical, before calling `.__eq__`? > > If python does not do it automatically, then at least in your example it > would be good to make g.__eq__ use the "self is other" test, before > doing anything expensive. Probably the problem would also be solved by > implementing rich comparison via __richcmp__ (not sure though).
DiGraph comparison is slower than it should be for sure. I already have plans to change that, even though I fear the messy code as I will have to deal with the usual multiedges/edge labels/loops subcases (and their combinations). I should also add the "self is other" test, but that would not change this example: the code computes a Hasse Diagram from g, and this second digraph is used as a parameter of Poset. Thus a comparison will be necessary anyway (g is not even immutable). > In any case, if there is a reason to have unique representation, then > ideally the defining data should be easy to compare. Evidently, a > dictionary lookup has to be involved for any kind of unique > represenation. I agree. I think that I can make DiGraph equality faster [1], but it will not be magic either. Testing equality of graphs will never be free, and I do think that there should be a way to not pay it if.... you see no need to. Nathann [1] especially in the very very very specific case of the digraphs used by posets -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
