Set up prism with both Vrep and Hrep

[kliem]

We set up the prism over a polyhedron with the double description.

Before:

sage: P = polytopes.permutahedron(6)                                                                                                                                                
sage: %time Q = P.prism()                                                                                                                                                           
CPU times: user 231 ms, sys: 7.92 ms, total: 239 ms
Wall time: 237 ms
sage: P = polytopes.hypercube(8)                                                                                                                                                    
sage: %time Q = P.prism()                                                                                                                                                           
CPU times: user 65.3 ms, sys: 28 µs, total: 65.3 ms
Wall time: 63.9 ms
sage: P = polytopes.cross_polytope(8)                                                                                                                                               
sage: %time Q = P.prism()                                                                                                                                                           
CPU times: user 39.4 ms, sys: 0 ns, total: 39.4 ms
Wall time: 38.6 ms
sage: P = polytopes.hypercube(6, backend='field')                                                                                                                                   
sage: %time Q = P.prism()                                                                                                                                                           
CPU times: user 3.47 s, sys: 3.97 ms, total: 3.48 s
Wall time: 3.48 s

After:

sage: P = polytopes.permutahedron(6)                                                                                                                                                                                                                                           
sage: %time Q = P.prism()                                                                                                                                                                                                                                                      
CPU times: user 56.7 ms, sys: 3.85 ms, total: 60.6 ms
Wall time: 59.8 ms
sage: P = polytopes.hypercube(8)                                                                                                                                                                                                                                               
sage: %time Q = P.prism()                                                                                                                                                                                                                                                      
CPU times: user 26.5 ms, sys: 0 ns, total: 26.5 ms
Wall time: 26.2 ms
sage: P = polytopes.cross_polytope(8)                                                                                                                                                                                                                                          
sage: %time Q = P.prism()                                                                                                                                                                                                                                                      
CPU times: user 33.7 ms, sys: 0 ns, total: 33.7 ms
Wall time: 33 ms
sage: P = polytopes.hypercube(6, backend='field')                                                                                                                                                                                                                              
sage: %time Q = P.prism()                                                                                                                                                                                                                                                      
CPU times: user 14.1 ms, sys: 0 ns, total: 14.1 ms
Wall time: 13.8 ms
sage: P = polytopes.hypercube(10, backend='field')                                                                                                                                                                                                                             
sage: %time Q = P.prism()                                                                                                                                                                                                                                                      
CPU times: user 32.3 ms, sys: 0 ns, total: 32.3 ms
Wall time: 31.8 ms

Component: geometry

Keywords: polyhedron, double description, precomputed, prism

Author: Jonathan Kliem

Branch/Commit: f75726d

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/32150

[sagetrac-git]

Changed commit from 41a6951 to f75726d

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

0cfc146	tiny improvements
f75726d	only compute prism once

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:3

LGTM.

[kliem]

comment:4

Thank you.

[vbraun]

Changed branch from u/gh-kliem/double_description_prism to f75726d