#20078: Minimal non faces of simplicial complexes: Improve speed
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Reporter: jipilab | Owner:
Type: | Status: new
enhancement | Milestone: sage-7.1
Priority: major | Keywords: simplicial complex, minimal
Component: PLEASE | nonface
CHANGE | Authors: Jean-Philippe Labbé
Merged in: | Report Upstream: N/A
Reviewers: | Branch:
Work issues: | Dependencies:
Commit: |
Stopgaps: |
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The current implementation to compute minimal non-faces of simplicial
complexes is really slow:
{{{
sage: SC = SimplicialComplex([(0,1,2),
(0,2,3),
(2,3,4),
(1,2,4),
(1,4,5),
(0,3,6),
(3,6,7),
(4,5,7)])
sage: %time SC.minimal_nonfaces()
CPU times: user 11 s, sys: 140 ms, total: 11.2 s
Wall time: 11.2 s
{(3, 4, 7), (5, 6), (0, 4), (0, 5), (3, 5), (4, 6), (2, 5), (0, 7), (1,
3), (1, 7), (1, 6), (2, 6), (2, 7)}
}}}
This is a difficult problem but it seems that the algorithm could be
improved with not too much efforts. I made a first try here:
{{{
sage: %time mnf(SC)
CPU times: user 21.3 ms, sys: 4.25 ms, total: 25.6 ms
Wall time: 26.6 ms
{{3, 4, 7}, {0, 7}, {0, 4}, {0, 5}, {3, 5}, {1, 7}, {2, 5}, {5, 6}, {1,
3}, {4, 6}, {1, 6}, {2, 6}, {2, 7}}
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/20078>
Sage <http://www.sagemath.org>
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