Opened 10 years ago
Closed 9 years ago
#13194 closed enhancement (fixed)
FaceFan and NormalFan should work with (non-lattice) polyhedra
Reported by: | mmarco | Owned by: | mhampton |
---|---|---|---|
Priority: | major | Milestone: | sage-5.9 |
Component: | geometry | Keywords: | toric |
Cc: | wstein, novoselt | Merged in: | sage-5.9.beta4 |
Authors: | Volker Braun | Reviewers: | Andrey Novoseltsev |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | #11763 | Stopgaps: |
Description (last modified by )
It would be nice if face/normal fans could be constructed from a generic (QQ-)polytope and not just from a lattice polytope:
sage: R.<x,y,z>=ZZ[] sage: f=x*R.random_element()+y*R.random_element()+z*R.random_element() sage: Q=f.newton_polytope() sage: NormalFan(Q) --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) /home/mmarco/sage-5.0/<ipython console> in <module>() /home/mmarco/sage-5.0/local/lib/python2.7/site-packages/sage/geometry/fan.pyc in NormalFan(polytope, lattice) 626 (N(0, 1), N(-1, 0)) 627 """ --> 628 rays = (polytope.facet_normal(i) for i in range(polytope.nfacets())) 629 cones = (vertex.facets() for vertex in polytope.faces(dim=0)) 630 fan = Fan(cones, rays, lattice=lattice, check=False) AttributeError: 'Polyhedron_QQ_ppl' object has no attribute 'nfacets'
Attachments (1)
Change History (11)
comment:1 Changed 10 years ago by
- Description modified (diff)
- Keywords polytope facets fan removed
- Type changed from defect to enhancement
comment:2 Changed 10 years ago by
- Status changed from new to needs_review
- Summary changed from Inconsistency in polytope nfacets. to FaceFan and NormalFan should work with (non-lattice) polyhedra
comment:3 Changed 10 years ago by
- Reviewers set to Andrey Novoseltsev
- Status changed from needs_review to needs_work
Normal fans require full-dimensional polytopes, but it is not necessary to contain the origin.
comment:4 Changed 10 years ago by
- Status changed from needs_work to needs_review
True, I removed the interior point check.
comment:5 Changed 10 years ago by
I think the normal fan is defined for non-compact polytopes as well - rays are normals to facets (hence we need full-dimensionality) and higher dimensional cones are given by smaller dimensional faces. I don't insist on implementing it, but perhaps NotImplementedError
is more suitable than ValueError
?
comment:6 Changed 10 years ago by
novoselt@sage ~/sage/devel/sage-main $ hg qapplied trac2607.patch trac2607-whitespace.2.patch trac_2607_renaming.3.patch trac2607-doctest-and-spacing.patch trac_12965_rational_class_group_lattice.patch trac_13052-is-positive-definite-RDF-v2.patch trac_12544_switch_cones_to_PointCollection_folded.patch trac_13191_auto_fan_2d.patch trac_13191_reviewer.patch trac_13194_polytope_fan_construct.patch
11 doctests fail in fan.py with this queue (on 5.1.rc1) with messages like
AttributeError: 'list' object has no attribute 'incident' AttributeError: 'Polyhedron_QQ_ppl' object has no attribute 'dilation'
Does this patch depend on new polyhedral code as well?
comment:7 Changed 10 years ago by
- Dependencies set to #11763
comment:8 Changed 9 years ago by
This patch doesn't require anything on top of sage-5.9.beta2.
Note the follow-up #14394 since I though that this ticket had been merged a long time ago.
comment:9 Changed 9 years ago by
- Keywords toric added
- Status changed from needs_review to positive_review
comment:10 Changed 9 years ago by
- Merged in set to sage-5.9.beta4
- Resolution set to fixed
- Status changed from positive_review to closed
NormalFan
takes a lattice polytope as argument, not any QQ-polytope:Having said that, it would be nice if any polytope would work.