#11360: The Rubik's Cube group in Sage doesn't support many basic operations
for a
dumb reason.
-----------------------------+----------------------------------------------
Reporter: was | Owner: jason, ncohen, rlm
Type: enhancement | Status: positive_review
Priority: minor | Milestone: sage-5.0
Component: graph theory | Keywords:
Work_issues: | Upstream: N/A
Reviewer: Nathann Cohen | Author:
Merged: | Dependencies:
-----------------------------+----------------------------------------------
Changes (by ncohen):
* status: needs_review => positive_review
* reviewer: => Nathann Cohen
Old description:
> We have
> {{{
> sage: G = CubeGroup()
> sage: G.order()
> Traceback (most recent call last):
> ...
> AttributeError: 'CubeGroup' object has no attribute '_gap_string'
> sage: G.sylow_subgroup(3)
> Traceback (most recent call last):
> ...
> AttributeError: 'CubeGroup' object has no attribute '_gap_string'
> }}}
>
> However, these things are all easily computable in Sage:
> {{{
> sage: G2 = PermutationGroup(G.gens())
> sage: G2.order()
> 43252003274489856000
> sage: G2.sylow_subgroup(3)
> Permutation Group with generators [(24,30,43)(32,48,38), ...
> }}}
New description:
We have
{{{
sage: G = CubeGroup()
sage: G.order()
Traceback (most recent call last):
...
AttributeError: 'CubeGroup' object has no attribute '_gap_string'
sage: G.sylow_subgroup(3)
Traceback (most recent call last):
...
AttributeError: 'CubeGroup' object has no attribute '_gap_string'
}}}
However, these things are all easily computable in Sage:
{{{
sage: G2 = PermutationGroup(G.gens())
sage: G2.order()
43252003274489856000
sage: G2.sylow_subgroup(3)
Permutation Group with generators [(24,30,43)(32,48,38), ...
}}}
Apply:
* [attachment:trac_11360-cubegroup.patch]
* [attachment:trac_11360-cubegroup2.patch]
--
Comment:
Helloooooo !!!
I guess this patch is more a "group theory" patch than "graph theory", but
it is not so complicated anyway. And I checked what I needed to know on
[1] `:-)`
Positive review to this patch !
By the way, I wondered about something. A colleague of mine is working on
graph automorphisms, and it seems our library on this aspect is pretty
poor. Can we do anything else than just "forward instructions to GAP" ? It
seems Sage's a long way to be a good alternative to their code.. Perhaps
it is not meant to be, however... I'd be glad to have an layman's opinion
on that though `:-)`
Nathann
[1] http://www.gap-system.org/Doc/Examples/rubik.html
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11360#comment:7>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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