#9798: Accelerate Polyhedron constructor
----------------------------+-----------------------------------------------
Reporter: vbraun | Owner: mhampton
Type: defect | Status: needs_review
Priority: major | Milestone:
Component: geometry | Keywords:
Author: Volker Braun | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Changes (by newvalueoldvalue):
* cc: mhampton, novoselt (added)
* status: new => needs_review
* author: => Volker Braun
Old description:
> I've run across some polytopes that can't be constructed in finite time
> because computing the facet and vertex adjacencies takes forever. Just
> computing the reduced H/V-representation takes just a few minutes. So I
> propose to '''not''' compute the adjacency data in the constructor, but
> only when needed. This requires patches to the `cddlib` spkg and to
> `polyhedra.py`
New description:
I've run across some polytopes that can't be constructed in finite time
because computing the facet and vertex adjacencies takes forever. Just
computing the reduced H/V-representation takes just a few minutes. So I
propose to '''not''' compute the adjacency data in the constructor, but
only when needed. This requires patches to the `cddlib` spkg and to
`polyhedra.py`
Also, make `cddlib` produce the same output ordering on all platforms
(#9926)
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Comment:
I updated the spkg at
http://www.stp.dias.ie/~vbraun/Sage/spkg/cddlib-094f.p8.spkg
Now it includes a random number generator (taken from GNU libc), so the
`cddlib` output ordering should be the same on all platforms.
The prerequisite patch has been merged into Sage 4.6.alpha0, so now would
be a good time to review this ticket :-)
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9798#comment:3>
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