On Mon, May 18, 2015 at 8:30 AM, Vincent Delecroix <20100.delecr...@gmail.com> wrote: > On 18/05/15 14:06, David Joyner wrote: >> On Mon, May 18, 2015 at 7:51 AM, Vincent Delecroix >> <20100.delecr...@gmail.com> wrote: >>> Moreover, for non oriented graph the Sage definition does not fit with >>> wikipedia... I opened the trac ticket >>> >>> http://trac.sagemath.org/ticket/18440 >>> >> >> Thank you. >> >> In case it's of any interest, the code I've been using privately >> allows for an arbitrary edge orientation (following Biggs). See below: > > Your code does not follow wikipedia definition where the entries belong > to {0, 1, 2} when the graph is not oriented. >
I always use edge-oriented graphs for the calculations I need (which I view as slightly different from directed graphs). What wikipedia refers to as an oriented incidence matrix is what I use. It needs to be fixed to follow the more general wikipedia definition. Also, to be clear, I think what you are calling a graph in your sagetrac ticket, some people call a multi-graph. And what you are calling an oriented graph in your sagetrac ticket, includes edge-oriented graphs, signed graphs, and directed graphs. If that is incorrect, please let me know. > Vincent > > -- > 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 post to this group, send email to sage-support@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/d/optout. -- 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 post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
