#17921: faster matching polynomial
-------------------------------------+-------------------------------------
Reporter: pernici | Owner:
Type: enhancement | Status: needs_info
Priority: major | Milestone: sage-6.6
Component: graph theory | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/pernici/ticket/17921 | 29612041a35d028109e61b09bba08ea9ec1f8e5e
Dependencies: | Stopgaps:
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Changes (by vdelecroix):
* status: needs_review => needs_info
Old description:
> ADD DESCRIPTION
>
> Added ``matching_generating_poly``, modified ``matching_polynomial``,
> added an option
> to ``permanental_minor_polynomial``, which for some graphs is faster than
> the previous
> algorithm.
>
> ``matching_generating_poly`` computes the matching generating polynomial
> on (possibly weighted) graphs; this is used in
> ``permanental_minor_polynomial``.
>
> The algorithm (see [ButPer]) uses polynomials on nilpotent elements,
> implemented in the class ``Hobj`` in matchpoly.pyx,
> and a greedy argument to order edges, contained in active_nodes.py
>
> This algorithm is much faster than the Godsil algorithm on large graphs.
>
> ``
> sage: from sage.graphs.matchpoly import matching_generating_poly
> sage: g = graphs.BuckyBall()
> sage: time sum(matching_generating_poly(g).coefficients())
> CPU times: user 184 ms, sys: 0 ns, total: 184 ms
> Wall time: 184 ms
> 1417036634543488
> ``
New description:
Added `matching_generating_poly`, modified `matching_polynomial`, added an
option
to `permanental_minor_polynomial`, which for some graphs is faster than
the previous
algorithm.
`matching_generating_poly` computes the matching generating polynomial
on (possibly weighted) graphs; this is used in
`permanental_minor_polynomial`.
The algorithm (see [!ButPer]) uses polynomials on nilpotent elements,
implemented in the class `Hobj` in matchpoly.pyx,
and a greedy argument to order edges, contained in active_nodes.py
This algorithm is much faster than the Godsil algorithm on large graphs.
{{{
sage: from sage.graphs.matchpoly import matching_generating_poly
sage: g = graphs.BuckyBall()
sage: time sum(matching_generating_poly(g).coefficients())
CPU times: user 184 ms, sys: 0 ns, total: 184 ms
Wall time: 184 ms
1417036634543488
}}}
--
Comment:
I clean the description of the ticket to make it readable. Could you try
to make it understandable?
--
Ticket URL: <http://trac.sagemath.org/ticket/17921#comment:6>
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