Opened 8 years ago

Last modified 7 years ago

#11763 closed enhancement

Parents for polyhedra — at Version 25

Reported by: vbraun Owned by: mhampton
Priority: major Milestone: sage-5.6
Component: geometry Keywords:
Cc: robertwb Merged in:
Authors: Volker Braun Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: #11634 Stopgaps:

Description (last modified by vbraun)

The Polyhedron class is, so far, free-standing with some sort of coercion for the base ring tacked manually. This ticket strives to add parents for polyhedra and make the base ring coercion work more naturally.

There will be 3 supported base rings:

  • ZZ (meaning that the polyhedron is a lattice polytope, that is, both H- and V-representation are defined over ZZ)
  • QQ
  • RDF

Apply:

Change History (32)

comment:1 Changed 8 years ago by novoselt

Would there be any benefit in supporting real fields of arbitrary precision?

comment:2 Changed 8 years ago by vbraun

We don't have an implementation of the double description algorithm for other base rings, so we wouldn't be able to compute anything.

Changed 8 years ago by vbraun

Initial patch

Changed 8 years ago by vbraun

Initial patch

comment:3 Changed 8 years ago by vbraun

  • Authors set to Volker Braun
  • Description modified (diff)
  • Status changed from new to needs_review

This is now ready for inclusion. Marshall, are you interested in reviewing this patch and its dependency? ;-)

comment:4 Changed 8 years ago by vbraun

  • Description modified (diff)

comment:5 Changed 8 years ago by vbraun

Fix comparison of H/V-representation objects:

sage: triangle = Polyhedron([(0,0), (1,0), (0,1)])
sage: ieq = triangle.inequality_generator().next()
sage: ieq == copy(ieq)
False

Now returns True, as it should.

Changed 8 years ago by vbraun

Updated patch

Changed 8 years ago by davidloeffler

Rebased for new patch at 11634

Changed 8 years ago by davidloeffler

Rebased for new patch at #11634

comment:6 Changed 8 years ago by davidloeffler

  • Description modified (diff)

The new patch I posted at #11634 broke these, so I rebased them.

Apply trac_11763_ZZ_polyhedron-rebase.patch, trac_11763_parents-rebase.patch

comment:7 Changed 8 years ago by davidloeffler

Apply trac_11763_zz_polyhedron-rebase.patch, trac_11763_parents-rebase.patch

(bloody patchbot!)

comment:8 Changed 8 years ago by davidloeffler

No matter what I do, the patchbot won't pick up the two patches above, so I've done a single qfolded patch. Hopefully this will now work!

comment:9 Changed 8 years ago by davidloeffler

  • Description modified (diff)

Changed 8 years ago by davidloeffler

Apply only this patch. Patch against 5.0.beta7

comment:10 Changed 8 years ago by davidloeffler

Sorry, I made a hash of rebasing the patch, so here's a new version.

comment:11 Changed 8 years ago by mhampton

This changes the behavior of the .vertices() method, returning "sage.geometry.polyhedron.representation.Vertex" objects instead of simple lists of coordinates. This breaks some code of mine, so I think there should be a deprecation warning before introducing this. I don't really like the behavior, but I see that .vertices_list() does return a list of lists of coordinates.

This patch also seems to slow things down a bit, but I haven't carefully tested that aspect.

comment:12 Changed 8 years ago by vbraun

The Vertex object implements the list interface, so any code that doesn't just test isinstance(-,list) should work fine. Plus, you can't really deprecate something unless you want to remove it later. I added the 'vertices_list` method so people can keep their broken code with minimal patching if they want.

comment:13 Changed 8 years ago by mhampton

Well, no, there is quite a bit of my code that does not work fine, and I am not talking about artificial test cases. Here is a shortened example of something this patch breaks:

c = polytopes.n_cube(3)
v = c.vertices()[0]
point(v)

This now gives a "TypeError?: 'sage.rings.integer.Integer' object does not support indexing".

comment:14 Changed 8 years ago by novoselt

For the record: #12541 and #12544 have a similar situation. I replaced tuples with tuple-like containers and some stuff got broken. As it turned out, it was not too difficult to fix it by eliminating some "hard typechecks", although they are still waiting for an approval. If this is the case here, perhaps it is also not too difficult to fix.

As I understand it, direct typechecking is not welcomed in either Python or Sage, so if the new class implements list interface, it should be OK to use in place of the old one. If it does break some code, it is a bug and it should be fixed before merging, but not a reason for avoiding the change entirely or inventing elaborate deprecation scheme...

comment:15 Changed 8 years ago by davidloeffler

  • Status changed from needs_review to needs_work
  • Work issues set to doctest failure

There is a doctest failing on 5.0.beta10, according to the patchbot (something to do with the new associahedron class from #10817)

comment:16 Changed 8 years ago by vbraun

  • Description modified (diff)
  • Status changed from needs_work to needs_review

The associahedron needed to be translated to the parent/element framework as well. I've fixed this. Also, I rediffed trac_11763-polyhedra_coercion_folded.2.patch because it only applied with some fuzz on sage-5.0.beta11

Changed 8 years ago by vbraun

Updated patch

comment:17 Changed 8 years ago by vbraun

  • Description modified (diff)

The final patch fixes the point() command to not make dumb type checks.

comment:18 Changed 8 years ago by vbraun

I noted a problem in the documentatation build, the updated patch fixes just that.

comment:19 Changed 8 years ago by davidloeffler

Apply trac_11763-polyhedra_coercion_folded.2.patch, trac_11763_fix_associahedron.patch, trac_11763_relax_typechecks.patch

(for patchbot)

comment:20 Changed 8 years ago by novoselt

I thought the point of having "Apply" section in the description was to make the patchbot happy, why does it need to be duplicated?..

comment:21 Changed 8 years ago by davidloeffler

It was previously applying the patches in an order other than that listed on the ticket description (with coercion_folded.2.patch last rather than first). I didn't think to check whether the patches were applying happily anyway; as it happens they were. Sorry for the noise!

comment:22 Changed 8 years ago by novoselt

Oh, I don't complain about your post - I complain about patchbot not figuring out what is the correct order despite a clear description ;-)

comment:23 Changed 8 years ago by chapoton

  • Status changed from needs_review to needs_work
  • Work issues changed from doctest failure to remove trailing whitespaces

comment:24 Changed 8 years ago by vbraun

  • Description modified (diff)
  • Status changed from needs_work to needs_review
  • Work issues remove trailing whitespaces deleted

We don't have a policy on trailing white space, so its completely useless bikeshedding to require it one way or another. But since this ticket is the special case where we create a new subdirectory layout, I used a simple sed script to remove trailing whitespace.

comment:25 Changed 8 years ago by vbraun

  • Description modified (diff)
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