Dear all, On Mon, Aug 03, 2020 at 09:38:07AM -0500, Ignat Soroko wrote: > I am computing a group of graph automorphisms by ad hoc methods, and have a > code (here gen is a partition of [1..n] corresponding to the degrees of > vertices): > > G:=Group(Union(List(gen,x->GeneratorsOfGroup(SymmetricGroup(x))))); > aut:=[]; > for g in G do > if ForAll([1..n-1],i->ForAll([i+1..n],j->m[i^g][j^g]=m[i][j])=true) then > Add(aut,g); > fi; > od; > Aut:=Group(aut);
I'd suggest using GRAPE package for such a task, which employs a reasonably efficient program (nauty) to compute graph automorphisms. Another package for the task is digraphs. > In some situations the resulting permutation group gets a huge generating > set, like the following one: > > Aut:=Group(Elements(SymmetricGroup(10))); > > and all operations with it become super slow. Is there a way to make GAP > pass to a smaller generating set? Unfortunately, commands like > SmallGeneratingSet(Aut); never terminate. > > Any hints? Use an efficient technique. HTH, Dima _______________________________________________ Forum mailing list Forum@gap-system.org https://mail.gap-system.org/mailman/listinfo/forum
