#8650 closed defect (fixed)
Extreme faces of Polyhedra are inconsistent
Reported by: | Andrey Novoseltsev | Owned by: | mhampton |
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Priority: | major | Milestone: | sage-4.4 |
Component: | geometry | Keywords: | |
Cc: | Merged in: | sage-4.4.alpha0 | |
Authors: | Marshall Hampton | Reviewers: | Andrey Novoseltsev |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
Let's look at the first face of each dimension of a polyhedron:
for lset in polytopes.cross_polytope(2).face_lattice().level_sets(): print lset[0]
The result is
(None, None) ((0,), (1, 2)) ((1, 2), (3,)) ((0, 1, 2, 3), (0, 1, 2, 3))
where the first tuple (None, None) corresponds to the empty face of the polytope. The first element gives generating vertices of this face (there are None). The second one should give all facets that contain this face. This should be the set of all facets of the polytope, not None. Similarly, for the last face, i.e. the whole polytope, we need to list all vertices belonging to this face (they are correctly listed), and all facets containing the polytope - there should be None.
While it should be easy to fix, I don't quite understand the code of face_lattice, so maybe someone else can do this...
Attachments (2)
Change History (8)
comment:1 Changed 13 years ago by
Changed 13 years ago by
Attachment: | trac_8650_patch0.patch added |
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comment:2 Changed 13 years ago by
Status: | new → needs_review |
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OK, I think the attached patch corrects things.
Changed 13 years ago by
Attachment: | trac_8650_fix_face_lattice_in_polyhedra.patch added |
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Apply this patch only
comment:3 Changed 13 years ago by
Authors: | → Marshall Hampton |
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Milestone: | → sage-4.4 |
Reviewers: | → Andrey Novoseltsev |
Status: | needs_review → positive_review |
Thank you! I have added the code above to the TESTS section.
comment:4 Changed 13 years ago by
Merged in: | → sage-4.4.alpha0 |
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Resolution: | → fixed |
Status: | positive_review → closed |
Merged "trac_8650_fix_face_lattice_in_polyhedra.patch" in 4.4.alpha0.
Oops. I wrote face_lattice, so this is my fault. Thanks for pointing it out. I think I can fix it pretty soon (hopefully today).