On 23 May 2013 13:52, Jason Grout <jason-s...@creativetrax.com> wrote: > On 5/23/13 12:34 AM, Dima Pasechnik wrote: >> >> can't the optional package nauty be used instead? Surely it can generate >> all these graphs very quickly. > > > Indeed, if all you are doing is generating the graphs, yes. The graph > database allows you to quickly query for graphs based on a number of > different cached parameter values, though. You could do a list > comprehension to calculate the parameters and discard the graphs you don't > want, but the convenience of a precomputed database sometimes is what you > want.
nauty (more precisely, geng) can do some of this on the fly : Usage: geng [-cCmtfbd#D#] [-uygsnh] [-lvq] [-x#X#] n [mine[:maxe]] [res/mod] [file] Generate all graphs of a specified class. n : the number of vertices mine:maxe : a range for the number of edges #:0 means '# or more' except in the case 0:0 res/mod : only generate subset res out of subsets 0..mod-1 -c : only write connected graphs -C : only write biconnected graphs -t : only generate triangle-free graphs -f : only generate 4-cycle-free graphs -b : only generate bipartite graphs (-t, -f and -b can be used in any combination) -m : save memory at the expense of time (only makes a difference in the absence of -b, -t, -f and n <= 28). -d# : a lower bound for the minimum degree -D# : a upper bound for the maximum degree - perhaps having a nice Sage interface to this is better than bothering with a database (which would be quite small too) Dima > > Thanks, > > Jason > -- 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?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
