ASKSAGE: Sage Q&A Forum - Latest question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Tue, 27 Sep 2011 07:35:00 -0500How to recognise DiGraph equivalencehttp://ask.sagemath.org/question/8348/how-to-recognise-digraph-equivalence/Hi -
I am trying to check that a "manual" calculation I did on posets is correct.
my starting point is a Matlab-generated upper-triangular 60x60 adjacency matrix M representing a DiGraph G or P=Poset(G); I have generated a minimal (ie covering relations only) 60x60 adjacency matrix from it in two ways. First by letting SAGE reduce it using PP=P.cover_relations(), and the other by reducing M "manually" in Matlab, then exporting that matrix Q to SAGE and using the same function on it to get it into the same format. I would like to show PP=Q in some sense.
I tried to check equality (==) between the graph objects, and the posets, and the graphs/posets obtained by re-setting the output of the cover_relations function to be a DiGraph all over again, and even setting those things to be adjacency matrices ... but even though I have laboriously checked that the 2 objects ARE indeed the same (by comparing the edges one-by-one), I nevertheless cannot get SAGE to agree!!
The output of the cover_relations function seems to be the sticking point - it is a sort-of matrix but not with any consistent ordering of the edges - hence even though the sets of edges are clearly the same, the different ordering seems to throw the comparison function off.
What am I missing please?
ThanksGaryMakTue, 27 Sep 2011 07:35:00 -0500http://ask.sagemath.org/question/8348/