Hi Dima,
On 2018-09-29, Dima Pasechnik <dimp...@gmail.com> wrote:
> On Sat, Sep 29, 2018 at 9:58 AM Simon King <simon.k...@uni-jena.de> wrote:
>>
>> On 2018-09-29, Simon King <simon.k...@uni-jena.de> wrote:
>> > Too bad: When the error occurs and I adjust the pool size then
>> > afterwards the previously defined objects in gap are gone.
>>
>> Additional problem: Even when I increase the memory limit sufficiently,
>> gap-via-pexpect takes substantially longer than libgap to compute the
>> double cosets. Why is that? There shouldn't be big traffic in the
>> interface whan just doing DC = G.DoubleCosetRepsAndSizes(N,N).
>
> Just use libGAP, perhaps?
> (and do the port of the corresponding functionality to libGAP, if you have
> time)
Rewriting my whole p_group_cohomology package to libGAP would be work
that I'd rather avoid.
Given a group defined in gap-via-pexpect, how to put it into libGAP?
Slight complication: My groups come with a name. Hence, the string
representation of the group is not good, libGAP doesn't understand it:
sage: G = gap.SymmetricGroup(6)
sage: G.SetName('"G"')
sage: libgap.eval(G)
...
ValueError: libGAP: Error, Variable: 'G' must have a value
So, how can I make gap produce data that allow to reconstruct the group?
Is libgap.Group(G.GeneratorsOfGroup()) the way to go? For permutation
groups probably it is. But for polycyclic groups, as provided by the
SmallGroups library?
sage: G = gap.SmallGroup(720,761)
sage: G
Group( [ f1, f2, f3, f4, f5, f6, f7 ] )
sage: libgap.Group(G.GeneratorsOfGroup())
...
ValueError: libGAP: Error, Variable: 'f1' must have a value
Concerning your hint to use the ACE package: After installing
gap_packages, DC = G.DoubleCosetRepsAndSizes(N,N) takes a very long
time in gap-via-pexpect (much longer than with libGAP), but so far it
didn't crash. But it is VERY long. So, rewriting everything to
libGAP might be the way to go after all. Sigh. Will be tedious work...
Worse: It seems to me that after installing gap_packages, libgap takes
long as well.
Best regards,
Simon
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