Hi Keith, > 2. A slightly modified version of the program works substantially > faster and with less memory; it's my understanding it will be in > the next version of gap. (Thanks Burkhard!)
Where is it? > 3. Crashing: ... (I described not the "Segmentation fault" type of crash, but the "recursion depth exceeded" / "memory exceeded" / "Holt/Plesken incomplete" types of failure.) > 4. Which group(s) of order 1024? I'd be intersted in seeing if the > new version of StructureDescription can handle them. Easier if you provide that new version. This happens in real life, not a group from some library. Andries >> The GAP manual advertises: >> "The method for StructureDescription exhibits the structure of >> the given group to some extend using the strategy outlined below. >> The idea is to return a possibly short string which gives some insight >> in the structure of the considered group and can be computed >> reasonably quickly." >> >> (manual typo: s/extend/extent/) >> >> It seems to me that the idea fails. Maybe it is meant to be used only >> on baby groups, say with fewer than 100 elements, but used on >> rather small groups it usually crashes after many hours. >> Reactions are: recursion depth overflow (at recursion depth 5000), or >> memory overflow (needs more than the 3GB allowed on the command line), >> or missing info in Holt/Plesken library. >> >> Other functions reveal the structure of the groups involved >> rather quickly. I wonder what StructureDescription tries to do >> that is so extremely expensive. _______________________________________________ Forum mailing list [email protected] http://mail.gap-system.org/mailman/listinfo/forum
