> > "for i_id, i in enumerate(self.vertex_iterator())" would be in order. And > > to obtain the id corresponding to v, I guess the best is to build a > > dictionnary associating each vertex to its index at the beginning of the > > algorithm.
Oh, sorry ! Beware when you write the reverse dictionary, for the order of the vertices in vertex_iterator may not be the same as the one returned by vertices() !!! > Well, I "need" it for Tuesday. ;-) But not desperately. Would the > backends for graphs easily/efficiently support something like > G.index(u) to get the integer behind a vertex u quickly and > easily? It seems this would be useful for all the places where the > code assumes vertices are integers (or at least ordered). Well, they already do this at Cython level, but I guess they do it the same way --> with a reverse dictionary. Recently I have spent some time over the Graph backend and I guess I will have several patches to write there... Especially because we now have iterators in Cython :-) Nathann -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
