Hi Fatemeh, You don't need to generate the partitions to determine the number of ways to partition an n-set. GAP has a function called Bell(n) that computes this number:
https://github.com/gap-system/gap/blob/master/lib/combinat.gi#L95-L105 that has complexity n^2. Kieran. > Message: 1 > Date: Mon, 18 Sep 2017 19:38:09 +0430 > From: fatemeh moftakhar <f.k.moftak...@gmail.com> > To: fo...@gap-system.org > Subject: [GAP Forum] Set Partitions > Message-ID: > <caoekhnjy7xme+lzzu1c8upmhy_fu2mdtj2rvf6tnlx5ctze...@mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Dear Colleagues, > > I need to the algorithm of computing the number of partitions of an n-set > in GAP. Could you please send me the address of a paper or a book that > contains such an algorithm? > My main question is complexity of the algorithm that GAP uses for > generating set partitions. I know the following paper that the complexity > of this algorithm is \theta(1.6). Is this complexity better than GAP > algorithm? > > M. C. ER, A fast algorithm for generating set partitions, The Computer > Journal, 31(3) (1988) 283-284. > > Best regards > Fatemeh Moftakhar > > > -- > Regards; > Miss Fatemeh Moftakhar > PhD Candidate, > Department of Pure Mathematics, > Faculty of Mathematical Sciences, > University of Kashan, Kashan, Iran _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
