Perhaps you can cheaply make it faster by first testing if two different poset have the same generating series ( if I remember correctly it just amount to compare the numbers of minimal elements, the number of elements juste above, etc, etc, etc...
Or you could just try for any serie to enumerate all the posets having the same serie ! Nathann On Nov 20, 3:42 am, Jason Grout <jason-s...@creativetrax.com> wrote: > Tom Boothby wrote: > > On Thu, Nov 19, 2009 at 4:14 PM, Florent Hivert > > <florent.hiv...@univ-rouen.fr> wrote: > >> Hi Jason, > > >>>> I'd like to generate all partially ordered sets of a given cardinality > >>>> upto > >>>> isomorphisms... They are in bijection with aclyclic, transitively reduced > >>>> directed graphs. Does anyone have an idea how to do that ? I can't > >>>> manage to > >>>> get this with nauty. > > >>> I'm sure there's a smarter way, but you could generate acyclic directed > >>> graphs and then transitively reduce them. > >> Yep ! That's a solution... I'll need then nauty again to remove isomorphic > >> duplicates. I'll probably go far enough for my problem with this methods > >> since > >> the algorithm I want to put behind seems to be vastly exponential in the > >> size > >> of the poset. I hope this will not break my conjecture... > > >> By the way, just to know, can this be achieved in plain sage without nauty > >> ? > > > Yes, it can. Read the documentation for digraphs(). > > Using the "augment" and "property" options might also speed up your > generation quite a bit, as you can control how these things are > generated (i.e., you can just generate acyclic transitively reduced > graphs, maybe). Nauty has similar hooks in C too. > > Thanks, > > Jason > > -- > Jason Grout -- 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
