Opened 2 years ago
Closed 2 years ago
#29568 closed defect (fixed)
Initialize polyhedra with backend cdd over RDF with both Vrepresentation and Hrepresentation
Reported by:  ghkliem  Owned by:  

Priority:  major  Milestone:  sage9.2 
Component:  geometry  Keywords:  inexact polyhedra, precomputed data 
Cc:  jipilab, ghLaisRast  Merged in:  
Authors:  Jonathan Kliem  Reviewers:  JeanPhilippe Labbé 
Report Upstream:  N/A  Work issues:  
Branch:  7e5ecaf (Commits, GitHub, GitLab)  Commit:  7e5ecaf79d9a90d36e4b83cd58846dcd6a13365e 
Dependencies:  Stopgaps: 
Description (last modified by )
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/sitepackages/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 3dimensional 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).
Change History (6)
comment:1 Changed 2 years ago by
 Branch set to public/29568
 Commit set to aa5ef80e50468ab04c644e59f3550a35e403fe02
 Description modified (diff)
 Summary changed from Initialize polyhedra with backend cdd with both Vrepresentation and Hrepresentation to Initialize polyhedra with backend cdd over RDF with both Vrepresentation and Hrepresentation
comment:2 Changed 2 years ago by
 Status changed from new to needs_review
comment:3 Changed 2 years ago by
 Branch changed from public/29568 to public/29568reb
 Commit changed from aa5ef80e50468ab04c644e59f3550a35e403fe02 to 7e5ecaf79d9a90d36e4b83cd58846dcd6a13365e
New commits:
7e5ecaf  initalize cdd with both Hrep and Vrep to deal with numerical inconsistency

comment:5 Changed 2 years ago by
 Reviewers set to JeanPhilippe Labbé
 Status changed from needs_review to positive_review
Looks good to me.
comment:6 Changed 2 years ago by
 Branch changed from public/29568reb to 7e5ecaf79d9a90d36e4b83cd58846dcd6a13365e
 Resolution set to fixed
 Status changed from positive_review to closed
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New commits:
initalize cdd with both Hrep and Vrep to deal with numerical inconsistency