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by joswig
09 Feb 2013, 10:01
Forum: Helpdesk
Topic: Trivial 0 >= -1 inequality among the facets
Replies: 3
Views: 5503

Re: Trivial 0 >= -1 inequality among the facets

But what you write means that the returned number of facets print $p->N_FACETS; is only correct if $p is bounded. (Of course I can live with that.) polymake's polytope semantics describes a projectively equivalent (bounded) polytope for every possibly unbounded polyhedron. Not every unbounded polyh...
by joswig
25 Jan 2013, 15:41
Forum: General Discussion
Topic: Public access to polymake svn repository?
Replies: 2
Views: 11570

Re: Public access to polymake svn repository?

We are in the middle of preparing svn-snapshots (which are supposed to be slightly more stable than a random checkout). You might want to try today's version 20130125. Stay tuned for more info in our wiki.
by joswig
17 Jan 2013, 11:26
Forum: Helpdesk
Topic: Integral polyhedra
Replies: 4
Views: 7712

Re: Integral polyhedra

First, a few general remarks: It is NP-complete to decide if a polyhedron contains one integer point or not. Checking if a polytope, given by its facets, is integral is also NP-hard [Papadimitriou and Yannakakis (1990)]. For variations and related results see the recent paper by Boros et al., Ann Op...
by joswig
14 Jan 2013, 19:06
Forum: Helpdesk
Topic: Integral polyhedra
Replies: 4
Views: 7712

Re: Integral polyhedra

It seems that there is a custom made piece of software for your needs: azove by Behle. There is even a polymake interface, install azove, and then do "reconfigure 'azove.rules';" within polymake's polytope application. This could be useful for your more tricky input. Please try it and give...
by joswig
31 Dec 2012, 11:11
Forum: General Discussion
Topic: rephrasing my vert(hom(p, q)) question
Replies: 1
Views: 11120

Re: rephrasing my vert(hom(p, q)) question

Everything works like described in Bogart, Contois and Gubeladze: Hom-Polytopes, arXiv:1111.3880 . The coordinates of Hom(P,Q) are grouped into dim Q blocks of length (dim P + 1). Each of these blocks of length dim P + 1 gives a column of the transformation. Since we are working with homogeneous coo...
by joswig
06 Dec 2012, 12:24
Forum: Helpdesk
Topic: Secondary Fans using gfan
Replies: 10
Views: 13427

Re: Secondary Fans using gfan

OK, there is a bug in apps/fan/rules/gfan.rules.

Please replace the line 41 by

Code: Select all

gfan_print_matrix($tempfile,eliminate_denominators_entire_affine($M->minor(All,[1..$M->cols()-1])));
Sorry for the inconvenience.
by joswig
03 Dec 2012, 11:59
Forum: Helpdesk
Topic: Secondary Fans using gfan
Replies: 10
Views: 13427

Re: Secondary Fans using gfan

Can you give me a hint what I am supposed to do here ?
Nothing.

polymake transformed your files into a new format. On the way it trashed the properties DIM and AMBIENT_DIM which became user functions. That's why you got a warning (but no error). No information lost in your data.
by joswig
20 Nov 2012, 09:01
Forum: Helpdesk
Topic: Interpreting vertices of Hom(p, q)
Replies: 2
Views: 4504

Re: Interpreting vertices of Hom(p, q)

You can force polymake to write out the labels: > $p=cube(2); > $q=new Polytope<Rational>(POINTS=>new Matrix<Rational>([[1, 0], [1, 1]]); > $hom=mapping_polytope($p, $q, relabel=>1); > print rows_labeled($hom->VERTICES,$hom->VERTEX_LABELS); v0*F1,v1*F1,v2*F0,v3*F0:1 1/2 0 1/2 v0*F1,v1*F1,v2*F1,v3*F1...
by joswig
12 Nov 2012, 18:19
Forum: Helpdesk
Topic: Regular subdivisons of point configurations
Replies: 2
Views: 4598

Re: Regular subdivisons of point configurations

Please use the function regular_subdivision: polytope > help "regular_subdivision"; functions/Subdivisions/regular_subdivision: regular_subdivision(points, weights) -> Array<Set<Int>> Compute a regular subdivision of the polytope obtained by lifting points to weights and taking the lower c...
by joswig
24 Sep 2012, 09:26
Forum: Helpdesk
Topic: 4D space : visualize polyhedra intersection
Replies: 3
Views: 6022

Re: 4D space : visualize polyhedra intersection

I grabbed the vertices from my polytopes and I'm gonna use a projection operator to plot them together in a 2d space. In general, this is one of the very few sensible options. A special situation occurs if the vertices of the two polytopes in 4-space are in convex position. Then one could introduce...

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