Sorry for not being clear. I meant I used geng —help. Apparently, the equal divide doesn’t help in my example case. Where is this geng.c file? If I modify geng.c, how should I build geng?
On Thu, Mar 21, 2019 at 9:58 PM John H Palmieri <jhpalmier...@gmail.com> wrote: > > > On Thursday, March 21, 2019 at 9:38:03 PM UTC-7, Ai Bo wrote: >> >> Saw this in the document: >> res/mod : only generate subset res out of subsets 0..mod-1 >> > > It would help if you gave some context for this. I'm guessing that most > Sage users won't know what "geng" is. I certainly didn't. I found by > searching the source code that you found this help message in the method > "nauty_geng" in graph_generators.py: you should have said this at the start > instead of just "saw this in the document". This makes it look like the > program "geng" comes from nauty. Now look at the nauty source code (there > is a tar file in the "upstream" directory, if you have a source code > version of Sage, also available at > http://files.sagemath.org/spkg/upstream/nauty/index.html). The nauty > manual says > > res/mod : only generate subset res out of subsets 0..mod-1 > > and > > See program text for much more information. > > The file geng.c says > > mod, res = a way to restrict the output to a subset. > All the graphs in G(n,mine..maxe) are divided into > disjoint classes C(0,mod),C(1,mod),...,C(mod-1,mod > ), > of very approximately equal size. > Only the class C(res,mod) is written. > > If the -x or -X switch is used, they must have > the > same value for different values of res; otherwise > the partitioning may not be valid. In this case > (-x,-X with constant value), the usual > relationships > between modulo classes are obeyed; for example > C(3,4) = C(3,8) union C(7,8). This is not true > if 3/8 and 7/8 are done with -x or -X values > different from those used for 3/4. > > > >> >> How is the output divided? >> >> I tried with : ../sage-8.6/local/bin/geng 6 -C 0/7 >> and then I iterated from 0/7, 1/7, 2/7, 3/7.... >> Why the output is 27, 21, 7, 1, 0, 0, ... >> >> How is the subset generated? >> >> Thank you. >> > -- > You received this message because you are subscribed to a topic in the > Google Groups "sage-devel" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/sage-devel/FJZoODSZK3Q/unsubscribe. > To unsubscribe from this group and all its topics, 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 https://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. > -- 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
