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Initialize polyhedra with backend cdd over RDF with both Vrepresentation and Hrepresentation #29568

@kliem

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@kliem

Setting up polyhedra with the shortest representation is not always the best choice for inexact polyhedra. Concretely, #29324 introduced a regression:

sage: P = polytopes.buckyball(exact=False) 
sage: P+P.center()
/srv/public/kliem/sage/local/lib/python3.7/site-packages/sage/geometry/polyhedron/backend_cdd.py:142: UserWarning: This polyhedron data is numerically complicated; cdd could not convert between the inexact V and H representation without loss of data. The resulting object might show inconsistencies.
  warn("This polyhedron data is numerically complicated; cdd could not convert between the inexact V and H representation without loss of data. The resulting object might show inconsistencies.")
A 3-dimensional polyhedron in RDF^3 defined as the convex hull of 60 vertices

On the other hand 2*P always threw this warning (also before #29200).

We use that we are given both Vrepresentation and Hrepresentation to use whichever works. It works if the calculated object has the correct length of Vrepresentation and Hrepresentation (that's the standard for cdd).

CC: @jplab @LaisRast

Component: geometry

Keywords: inexact polyhedra, precomputed data

Author: Jonathan Kliem

Branch/Commit: 7e5ecaf

Reviewer: Jean-Philippe Labbé

Issue created by migration from https://trac.sagemath.org/ticket/29568

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