#17216: Poset / LatticePoset: [meet|join]matrix algorithm
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Reporter: jmantysalo | Owner:
Type: enhancement | Status: needs_info
Priority: major | Milestone: sage-6.4
Component: combinatorics | Resolution:
Keywords: | Merged in:
Authors: Jori Mäntysalo | Reviewers: Nathann Cohen
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/jmantysalo/poset___latticeposet___meet_join_matrix_algorithm|
a649be931b249028ff1e5961fc948c2daf50c695
Dependencies: | Stopgaps:
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Comment (by ncohen):
> Has anyone checked that we do get speedups in meet/join matrix?
Look at the code, and you will see that the algorithm never changed. It is
only code simplification. For instance a call to 'max' instead of
computing the max by hand, for instance list-comprehension instead of
successive calls to 'append'. And a copy of a matrix is avoided too.
> For the definition of a lattice, I've also been told you want a
''unique'' meet and join. Otherwise just the existence is something like
regular poset, sorry I forget the exact term right now.
Travis, please read the code for your question is answered there.
> Also could you make the very minor change:
Please don't change the status of a ticket that has been reviewed unless
you see something which is actually wrong. Something more important than
moving a 'for' around.
Nathann
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Ticket URL: <http://trac.sagemath.org/ticket/17216#comment:14>
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