#11523: Implementation of Cohen-Macaulay test for simplicial complexes
------------------------------------------------------------------+---------
Reporter: stumpc5 |
Owner: malb
Type: enhancement |
Status: needs_review
Priority: major |
Milestone: sage-5.6
Component: commutative algebra |
Resolution:
Keywords: Cohen-Macaulay, homology, simplicial complexes | Work
issues: further improvement of _enlarge_subcomplex
Report Upstream: N/A |
Reviewers: Travis Scrimshaw
Authors: Christian Stump | Merged
in:
Dependencies: #12587 |
Stopgaps:
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Changes (by tscrim):
* reviewer: => Travis Scrimshaw
* dependencies: => #12587
Old description:
> Simplicial complexes were lacking a method to test Cohen-Macaulayness.
>
> In order to implement this method, some other methods are improved,
> namely a hash function is implemented, and _enlarge_subcomplex has become
> faster.
>
> For convinience, I also added a face_iterator.
>
> Remark: the new line
>
> {{{
> int_facets = set( a.set().intersection(f_set) for a in new_facets )
> }}}
>
> in _enalarge_subcomplex improved speed for computing the homology by 65%
> (in the example I looked at -- needs to be verified). This method still
> has the potential to be speeded a lot, and it is responsible for a lot
> cpu time when computing the homology.
>
> I also added a second version using parallel tests on multiple cpus.
New description:
Simplicial complexes were lacking a method to test Cohen-Macaulayness.
In order to implement this method, some other methods are improved, namely
a hash function is implemented, and _enlarge_subcomplex has become faster.
For convinience, I also added a face_iterator.
Remark: the new line
{{{
int_facets = set( a.set().intersection(f_set) for a in new_facets )
}}}
in _enalarge_subcomplex improved speed for computing the homology by 65%
(in the example I looked at -- needs to be verified). This method still
has the potential to be speeded a lot, and it is responsible for a lot cpu
time when computing the homology.
I also added a second version using parallel tests on multiple cpus.
-----
Apply only: [attachment:trac_11523-cohen_macaulay_complex-cs-jhp-review-
ts.patch]
--
Comment:
Hey Christian and John,
This did not apply against #12587, so I did the very minor rebase in my
review patch (it contains the entire patch; sorry if I overstepped here).
I also made some minor docstring changes: some formatting and moved the
note about the exception in a `.. NOTE::` block. If you agree with the
changes, feel free to set this to positive review.
Thanks for your work on this, I plan on putting this to good use,[[BR]]
Travis
For patchbot:
Apply only: trac_11523-cohen_macaulay_complex-cs-jhp-review-ts.patch
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11523#comment:14>
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