Hello! Thanks! I wasn't aware of libgap! One more followup question. Say I want to compute the orbits of the CubeGraph of order 10. The description of respective automorphism group seems to be to heave for libgap
==== sage: G = graphs.CubeGraph(10) sage: G.relabel() sage: A = G.automorphism_group() sage: libgap(A) python: libgap.c:186: libgap_get_input: Assertion `strlen(libGAP_stdin_buffer) < length' failed. === Is there a way to overcome this limitation? Best, Jernej On Tuesday, 22 March 2016 14:18:56 UTC+1, Dima Pasechnik wrote: > > > > On Tuesday, March 22, 2016 at 1:09:07 PM UTC, Dima Pasechnik wrote: >> >> use libgap: >> >> sage: g=libgap.SymmetricGroup(7) >> sage: g.Orbits(tuples([1..7],2),libgap.OnTuples) >> [ [ [ 1, 1 ], [ 2, 2 ], [ 3, 3 ], [ 4, 4 ], [ 5, 5 ], [ 6, 6 ], [ 7, 7 ] >> ], [ [ 1, 2 ], [ 2, 3 ], [ 2, 1 ], [ 3, 4 ], [ 1, 3 ], [ 3, 2 ], [ 4, 5 ], >> [ 2, 4 ], [ 4, 3 ], [ 3, 1 ], [ 5, 6 ], [ 3, 5 ], [ 1, 4 ], [ 5, 4 ], [ 4, >> 2 ], [ 6, 7 ], [ 4, 6 ], [ 2, 5 ], [ 6, 5 ], [ 5, 3 ], [ 4, 1 ], [ 7, 1 ], >> [ 5, 7 ], [ 3, 6 ], [ 1, 5 ], [ 7, 6 ], [ 6, 4 ], [ 5, 2 ], [ 7, 2 ], [ 6, >> 1 ], [ 4, 7 ], [ 2, 6 ], [ 1, 7 ], [ 7, 5 ], [ 6, 3 ], [ 5, 1 ], [ 6, 2 ], >> [ 3, 7 ], [ 1, 6 ], [ 2, 7 ], [ 7, 4 ], [ 7, 3 ] ] ] >> >> if you only need representatives, you can just use map: > > map(lambda x: x[0], g.OrbitsDomain(tuples([1..7],2),libgap.OnTuples)) > > (Here I used OrbitsDomain, which you should use for efficiency if you know > that your set is invariant under your > group) > > >> On Tuesday, March 22, 2016 at 9:19:18 AM UTC, Jernej wrote: >>> >>> Hello! >>> >>> I have a few questions concerning GAP interface in Sage 7.x. >>> >>> I have a permutation group G acting on a set S and I would like to >>> compute the representatives of the orbits of G acting on k-sets of S. >>> >>> I recall that a while ago I could do the following (as seen on this >>> example >>> http://ask.sagemath.org/question/9652/orbits-on-group-actions-acting-on-sets/?answer=14470#post-id-14470 >>> ) >>> >>> ==== >>> sage: g=SymmetricGroup(7) >>> sage: >>> gap("Orbits("+str(g._gap_())+","+str(tuples([1..7],2))+",OnTuples)") >>> ==== >>> >>> and yes, it works in Sage 6.x. However, in Sage 7.x one gets the >>> following error >>> >>> ==== >>> TypeError: Gap terminated unexpectedly while reading in a large line: >>> Gap produced error output >>> Error, Permutation: cycles must be disjoint and duplicate-free >>> ==== >>> >>> Given this, I have the following questions >>> >>> - What is the proper way to call gap in Sage 7x t obtain the orbits of a >>> group G acting on k-sets of a set S? >>> - (GAP question) I recall there is a way to return only the >>> representatives of the orbits? Anyone happens to recall the right GAP >>> command for that? >>> - Does it make sense to add an option for various group actions to Sage >>> directly (as is already done for specific orbits ) ? >>> >>> Best, >>> >>> Jernej >>> >> -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
