#9798: Accelerate Polyhedron constructor
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Reporter: vbraun | Owner: mhampton
Type: defect | Status: needs_info
Priority: major | Milestone:
Component: geometry | Keywords:
Author: Volker Braun | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Comment(by dimpase):
Replying to [comment:5 vbraun]:
> 1. I debugged it some more and apparently the code that uses random
numbers ends up not being called in the code path. Which raises the
question again, how does cddlib manage to depend on the architecture...
I'll change the `polyhedra.py` to sort the cddlib output for now.
>
> 2. According to the (sparse) cdd manual, it exactly does that: solve a
LP to get the adjacency data. There is a bit of a combinatorial explosion
in high dimension and number of vertices, I guess.
Sorry, I don't get it. Computing the dual description is well-known to be
much more expensive in general than computing the vertex adjacencies - the
latter is polynomial-time, the former is certainly not...
>
> The other motivation for this ticket is that we can then start and
replace `libcdd`s implementation of the dual description with a better
one. In particular I'm eying a cythonized version of the Parma Polyhedra
Library, but we need at least cython 0.13 for C++.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9798#comment:8>
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