#13391: WeylCharacterRing improvement
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Reporter: bump | Owner: sage-combinat
Type: enhancement | Status: new
Priority: major | Milestone: sage-5.3
Component: combinatorics | Resolution:
Keywords: WeylCharacterRing, Lie | Work issues:
Report Upstream: N/A | Reviewers:
Authors: Daniel Bump | Merged in:
Dependencies: | Stopgaps:
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Description changed by bump:
Old description:
> The multiplication algorithm for WeylCharacterRings is changed by this
> patch to an algorithm based on the Brauer-Klimyk formula. This algorithm
> is asymmetric, so that a*b and b*a are equal but computed differently. It
> gives a modest speedup for sage -t weyl_characters.py but for tasks it is
> a dramatic improvement. As an example, create the spin character of
> Spin(9):
>
> sage: B4=WeylCharacterRing("B4",style="coroots")
> sage: spin=B4(0,0,0,1)
>
> Now try raising this to different powers before and after the patch.
New description:
The multiplication algorithm for {{{WeylCharacterRings}}} is changed by
this patch to an algorithm based on the Brauer-Klimyk formula. This
algorithm is asymmetric, so that a*b and b*a are equal but computed
differently. It gives a modest speedup for sage -t weyl_characters.py but
for tasks it is a dramatic improvement. As an example, create the spin
character of Spin(9):
{{{
sage: B4=WeylCharacterRing("B4",style="coroots")
sage: spin=B4(0,0,0,1)
}}}
Now try raising this to different powers before and after the patch.
--
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13391#comment:1>
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