#19583: random triangulation as simplicial complex
-------------------------------------+-------------------------------------
Reporter: chapoton | Owner:
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-7.1
Component: algebraic | Resolution:
topology | Merged in:
Keywords: random simplicial | Reviewers:
complex | Work issues:
Authors: Frédéric Chapoton | Commit:
Report Upstream: N/A | 5e465924db248460f0a20da334cd4b1f8499adc7
Branch: u/chapoton/19583 | Stopgaps:
Dependencies: |
-------------------------------------+-------------------------------------
Changes (by ncohen):
* status: needs_review => needs_work
Comment:
> Some timings
> {{{
> sage: %timeit simplicial_complexes.RandomTwoSphere(1000).graph()
> 1 loops, best of 3: 769 ms per loop
> sage: %timeit graphs.RandomTriangulation(1000)
> 1 loops, best of 3: 189 ms per loop
> }}}
Some timings:
{{{
sage: %timeit simplicial_complexes.RandomTwoSphere(1000)
1 loops, best of 3: 246 ms per loop
sage: %timeit graphs.RandomTriangulation(1000)
1 loops, best of 3: 222 ms per loop
}}}
That's what happens when you replace the last line of `RandomTwoSphere`
this way:
{{{
#!diff
- return SimplicialComplex(triangles)
+ return triangles
}}}
Another timing:
{{{
sage: %timeit simplicial_complexes.RandomTwoSphere(1000)
1 loops, best of 3: 269 ms per loop
sage: %timeit graphs.RandomTriangulation(1000)
1 loops, best of 3: 219 ms per loop
}}}
That's what happens when you do the following replacement instead:
{{{
- return SimplicialComplex(triangles)
+ return SimplicialComplex(triangles,maximality_check=False)
}}}
Once this (second) replacement is done, here is the effect on the `.graph`
function:
{{{
sage: %timeit simplicial_complexes.RandomTwoSphere(1000).graph()
1 loops, best of 3: 345 ms per loop
sage: %timeit graphs.RandomTriangulation(1000)
1 loops, best of 3: 222 ms per loop
}}}
If that is still too much for your (I assume computer-intensive) needs, it
seems that the .graph function is unnecessarily slow
{{{
sage: def simplex_to_graph(S):
g = Graph()
for S in S._facets:
g.add_cycle(g)
return g
sage: %timeit simplex_to_graph(simplicial_complexes.RandomTwoSphere(1000))
1 loops, best of 3: 288 ms per loop
sage: %timeit graphs.RandomTriangulation(1000)
1 loops, best of 3: 226 ms per loop
}}}
So please stop messing around by moving around blocks of 5 lines, and keep
only one of these two functions (unless you still find the speed penalty
too big).
Nathann
--
Ticket URL: <http://trac.sagemath.org/ticket/19583#comment:25>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
