#11625: speed up "remove_faces" for simplicial complexes
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Reporter: jhpalmieri | Owner: jhpalmieri
Type: enhancement | Status: new
Priority: minor | Milestone: sage-4.7.2
Component: algebraic topology | Keywords: simplicial remove_face
Work_issues: | Upstream: N/A
Reviewer: | Author: John Palmieri
Merged: | Dependencies:
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The attached patch, taken from a [http://ask.sagemath.org/question/521
/why-remove_face-uses-alexander-duality discussion on ask.sagemath.org],
speeds up `remove_face` for large simplicial complexes. For smaller ones,
it is comparable, perhaps a little slower, but the speed-up for large ones
is significant.
Before the patch:
{{{
sage: S = range(1,8)
sage: timeit('Z = SimplicialComplex(S, [S]); Z.remove_face([1,2,3])')
625 loops, best of 3: 767 µs per loop
sage:
timeit('SimplicialComplex(10,[[0,1,2,3,4,5,6],[1,2,3,4,5,6,7],[0,1,2,4,5,6,7],[0,1,2,3,5,6,7],[0,1,2,3,4,5,7]]).remove_face(Simplex([1,2,5]))')
5 loops, best of 3: 42.2 ms per loop
}}}
After the patch:
{{{
sage: S = range(1,8)
sage: timeit('Z = SimplicialComplex(S, [S]); Z.remove_face([1,2,3])')
625 loops, best of 3: 835 µs per loop
sage:
timeit('SimplicialComplex(10,[[0,1,2,3,4,5,6],[1,2,3,4,5,6,7],[0,1,2,4,5,6,7],[0,1,2,3,5,6,7],[0,1,2,3,4,5,7]]).remove_face2(Simplex([1,2,5]))')
125 loops, best of 3: 1.79 ms per loop
}}}
The original idea (from ask.sagemath.org) is by "EmersonL", and John
Palmieri modified it and wrote the actual patch.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11625>
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