Ticket #2937 (closed defect: fixed)
defects in polyhedra, 3d-gfan rendering
|Reported by:||mhampton||Owned by:||mhampton|
|Component:||geometry||Keywords:||polyhedra, convex hull, polytope, gfan|
Description (last modified by mabshoff) (diff)
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).