Scott Anderson wrote: > Hello to all, > > I am constructing codes over \F_9 and would like to > compute the automorphism groups of these codes. (I > have the Guava package installed so as to be able to > deal with codes in general.) I seem to be running > beyond some physical limitation of Gap, at least on > my (sigh) Windows PC. >
I'm not sure what you mean by "physical limitations". If you have already tried using the -o option described in http://www.gap-system.org/Manuals/doc/htm/ref/CHAP003.htm#SECT001 then probably there is not much you can do with whatever RAM you have. > Is there some way to compute automorphism groups for > such codes in a way that splits up the work (or > something) so my computer doesn't gag on it? Or > would it be helpful to ask the larger Unix computer > at the University to do this work? > I don't know of a way to split up the work. The GAP code calling the C code due to Leon is only implemented for binary codes. That C code GAP calls should work for non-binary codes as well but is not implemented in the non-binary case. (I tried to do this once and never could get it to work properly.) Honestly, Leon's code needs to be rewritten from scratch, but short of this you could try to get GAP to call the C code in the non-binary case. You would need to read Leon's documentation (which is very sketchy), included with GUAVA in the src/leon/doc subdirectory. > Any advice is appreciated. > You can get an upper bound on the group by using Thomas Breuer's MatrixAutomorphisms http://www.gap-system.org/Manuals/doc/htm/ref/CHAP069.htm#SECT020 Just put all the codewords of a given weight into a matrix (each row is a codeword of weight 10 say) and apply the function. Generally, the automorphism group computing ability of GUAVA is poor. There are even known bugs in it http://cadigweb.ew.usna.edu/%7Ewdj/gap/GUAVA/guava2do.html > Cheers, > Scott Anderson > _______________________________________________ > Forum mailing list > Forum@mail.gap-system.org > http://mail.gap-system.org/mailman/listinfo/forum > > _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
