#19018: More SRGs using Regular Symmetric Hadamard matric with Constant Diagonal
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Reporter: | Owner:
ncohen | Status: needs_review
Type: | Milestone: sage-6.9
enhancement | Resolution:
Priority: major | Merged in:
Component: graph | Reviewers:
theory | Work issues:
Keywords: | Commit:
Authors: | 6893ad1163b8c636fe4f54e3ff838ccad85f4d5b
Nathann Cohen | Stopgaps:
Report Upstream: N/A |
Branch: |
u/ncohen/19018 |
Dependencies: |
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Comment (by ncohen):
> huh? Here is an experiment with GAP, which is almost instant to run:
Oh. Good news. Well, the best would be to rely on GAP for these
computations then, for Sage does it *very* slowly.
> in your case the group will be given by 3 permutation generators, but
this will only make it even faster.
If you can make it work fast in Sage, I have no objection. Here is the
code I used to generate it:
{{{
from sage.groups.finitely_presented import FinitelyPresentedGroup
G = FreeGroup('x,y,z')
x,y,z = G.gens()
rels =
(x**5,y**5,z**4,x*y*x**(-1)*y**(-1),z*x*z**(-1)*x**(-2),z*y*z**(-1)*y**(-2))
G = FinitelyPresentedGroup(G,rels)
x,y,z = G.gens()
H = G.as_permutation_group()
L=["120","140","200","210","201","401","411","321","002","012","022","042","303","403","013","413","240","031","102","323","300","231","132","133","310","141","142","233","340","241","202","333","410","341","222","433","430","441","242","302","312","322","332","442","143"]
L = map(lambda x:map(int,x),L)
L = [G(x**xx*y**yy*z**zz) for xx,yy,zz in L]
GG = Graph()
for v in G:
for u in L:
uv = u*v
GG.add_edge([v]+[x for x in G if x==uv])
print GG.size()
}}}
> How hard is to say that in a comment that you used pds such-and-such for
group such-and-such?
I just do not care at all. That's why I did not. Can you acknowledge that
others can have a different view on this?
I will add a commit, just to end the discussion.
Nathann
--
Ticket URL: <http://trac.sagemath.org/ticket/19018#comment:19>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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