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 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.
