id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
22455,_facet_adjacency_matrix not working correctly for non-fulldimensional polyhedra,Christoph Pegel,,"The method `_facet_adjacency_matrix` of the `Polyhedron` class produces a wrong matrix for polyhedra that are not of same dimension as their ambient space. For example,
{{{
sage: s = polytopes.simplex(2)
sage: s._facet_adjacency_matrix()
[0 1 1 1]
[1 0 0 0]
[1 0 0 0]
[1 0 0 0]
}}}
while it should return
{{{
sage: s._facet_adjacency_matrix()
[0 1 1]
[1 0 1]
[1 1 0]
}}}
The problem is that what is being checked is the ambient H-representation of some face being of length 2, which is interpreted as ""2 facets are intersecting"". This approach doesn't work for codimension not equal to 0.
I have attached a proposed patch that takes codimension into account.",defect,closed,major,sage-8.2,geometry,fixed,"polyhedron facets, days88",Jean-Philippe Labbé Moritz Firsching Vincent Delecroix,,"Christoph Pegel, Jean-Philippe Labbé","Vincent Delecroix, Frédéric Chapoton",N/A,,fb5bf91a020abee42a758723bd04abec416c8090,fb5bf91a020abee42a758723bd04abec416c8090,,