-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dear Forum,
I have the following data: - - A permutation group G; - - a set of objects obj; - - an action function. I would like to get the following: - - The union D of the orbits of obj under G (not necessarily sorted); - - the action H of G on D; - - orbit representatives. What I do is the following: orbits := Orbits(G, obj, action); representatives := List(orbits, Representative); D := Union(orbits); # sorted to accelerate the next step H := Action(G, D, action); This works well when action is a standard action such as OnSetsSets. However, for custom actions this can be very slow, suggesting that different algorithms are used. (In some of my examples, D has a million elements.) Is there a way in GAP4 to accelerate this process, for example by providing hash functions? In GAP3 there existed a solution in the contributed file coco.grp by Theißen based on work by Faradzev et al. The question is whether there is a better way than porting that file to GAP4. Regards, Sven Reichard. - -- Institut für Algebra TU Dresden -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEVAwUBUZXwI2FjB3Gki4XVAQJrDgf+IdzNftD5zutKuXm/7vOWQhSOe6ZdeJ8p N+FWYHgXYuHfHPrXquv/iUzVKRaADu01+enk/T9sYIr6oEorcAO5GS0uh/5yhBSq IqL5jsvkyCbrW3jN8sjGUZanGw5z81cjx5VoigYuaON8VMB8qGMQ6w20B+0XdTss 29YZJZz1r2JMNB/Lfx7iiqHCRalfK1+qnnvimro404H2jc+sjvGH83nh6z3uZLy4 eaDBOaJgI2Uz8Nz3SL2KBEzhQ02Ipem3jEC37izS9Or20zotcog/G3v0uLsy10/G y7mcQ0lfhxH4PwQ1OpTbvFD4WHNQ1riMTmG5qtZgP9d7uymKBssmMA== =JAOJ -----END PGP SIGNATURE----- _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
