Opened 12 years ago

Closed 12 years ago

#2937 closed defect (fixed)

defects in polyhedra, 3d-gfan rendering

Reported by: mhampton Owned by: mhampton
Priority: major Milestone: sage-3.0.2
Component: geometry Keywords: polyhedra, convex hull, polytope, gfan
Cc: Merged in:
Authors: Reviewers:
Report Upstream: Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description (last modified by mabshoff)

Currently there are major issues in polyhedra.py (see #2844), which also affect 3d rendering of Groebner gfans - for example, the following doesn't work:

sage: R4.<x,y,z,w> = PolynomialRing(QQ,4)
sage: idnp = R4.ideal([x*y*z+x^2*z-x*y,x*w^2-z,x*w^4+x*z])
sage: gfnp = idnp.groebner_fan()
sage: a = gfnp.render3d()

I (Marshall Hampton) am actively fixing these issues but I don't have a patch yet. There are two main problems: 1) I didn't handle unbounded polyhedra well (which is what causes the above problem) and 2) properties such as facial_incidences can be wrong because of vertex reordering by cddlib. I should have a patch that fixes those problems and adds some rendering enhancements by 5/1/2008 (or earlier).

Change History (3)

comment:1 Changed 12 years ago by mhampton

  • Status changed from new to assigned

Once again, this time with feeling!:

Currently there are major issues in polyhedra.py (see #2844), which also affect 3d rendering of Groebner gfans - for example, the following doesn't work:

sage: R4.<x,y,z,w> = PolynomialRing(QQ,4) 
sage: idnp = R4.ideal([x*y*z+x2*z-x*y,x*w2-z,x*w4+x*z]) 
sage: gfnp = idnp.groebner_fan() 
sage: a = gfnp.render3d()

I (Marshall Hampton) am actively fixing these issues but I don't have a patch yet. There are two main problems: 1) I didn't handle unbounded polyhedra well (which is what causes the above problem) and 2) properties such as facial_incidences can be wrong because of vertex reordering by cddlib. I should have a patch that fixes those problems and adds some rendering enhancements by 5/1/2008 (or earlier).

comment:2 Changed 12 years ago by mabshoff

  • Description modified (diff)

comment:3 Changed 12 years ago by mabshoff

  • Resolution set to fixed
  • Status changed from assigned to closed

This issue has been fixed by merging #2716:

[22:34] <mhampton> mabshoff: I just figured out why I was confused.  #2716 took long 
enough to get in that you had me rebase it, and I put in stuff that I had meant for #2937
[22:34] <-- roed has left this server (Read error: 110 (Connection timed out)).
[22:34] <mhampton> So #2937 can be closed

Cheers,

Michael

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