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by joswig
18 Feb 2022, 12:07
Forum: Helpdesk
Topic: Betti numbers wrong for a patchworked curve ?
Replies: 3
Views: 3689

Re: Betti numbers wrong for a patchworked curve ?

Our implementation is slightly more general than primitive patchworking; it covers what is sometimes is called "combinatorial patchworking" in the literature. This means, we require that the lattice points (@my_monomials in your case) correspond to the entire set of monomials in, say, n va...
by joswig
27 Jan 2022, 20:30
Forum: Helpdesk
Topic: Visualization bug(?) in Polymake 4.6
Replies: 3
Views: 12427

Re: Visualization bug(?) in Polymake 4.6

We did make changes concerning threejs in order to obtain correct visualization for https://www.matchthenet.de/xmas. And I can confirm your problem.

Requires an investigation. Stay tuned.
by joswig
12 Jan 2022, 12:04
Forum: General Discussion
Topic: Convex Decomposition
Replies: 5
Views: 17306

Re: Convex Decomposition

That does not have unique solutions. Instead the set of such solutions forms a polyhedron in the parameter space (= coefficients of the linear combinations).
by joswig
12 Jan 2022, 09:30
Forum: General Discussion
Topic: Convex Decomposition
Replies: 5
Views: 17306

Re: Convex Decomposition

Sorry, I don't understand the question.

Is it that P_2 is a subpolytope of P_1, and you want to find those vcertices of P_1 which are not vertices of P_2?
by joswig
25 Oct 2021, 17:44
Forum: Helpdesk
Topic: Saving Polytope Vertices to CSV or TXT
Replies: 1
Views: 2955

Re: Saving Polytope Vertices to CSV or TXT

Your command sequence > $p = cube(3); > print($p->VERTICES); > save_data($p->VERTICES, "my_vertices.txt"); is perfectly OK; the result is a JSON file (format defined by polymake) which contains just one matrix plus a bit of metadata. If you want the matrix (coefficients separated by blanks...
by joswig
28 Sep 2021, 10:23
Forum: General Discussion
Topic: how to define integer polytope by matrix representation
Replies: 6
Views: 18836

Re: how to define integer polytope by matrix representation

Your example has a lineality space of positive dimension. polytope > $p = new Polytope(INEQUALITIES=>[[13,-6,0,-7,0,-9,0],[11,0,-8,0,-5,0,-6]],EQUATIONS=>[[-1,1,1,0,0,0,0],[-1,0,0,1,1,0,0],[-1,0,0,0,0,1,1]]); polytope > print $p->VERTICES; 1 -1/4 5/4 1 0 5/6 1/6 0 1 -1 0 0 -2/3 2/3 0 1 -1 0 0 -4/3 4...
by joswig
27 Sep 2021, 10:13
Forum: General Discussion
Topic: how to define integer polytope by matrix representation
Replies: 6
Views: 18836

Re: how to define integer polytope by matrix representation

You can specify polyhedra in terms of INEQUALITIES and EQUATIONS.
Asking for VERTICES then triggers a dual convex hull computation.

Please see tutorial.

The web version of polymake runs in a sandbox. So, by design, you cannot read from or write to files.
by joswig
20 Aug 2021, 12:59
Forum: General Discussion
Topic: Mixed volume -> edge matrix is singular?
Replies: 4
Views: 21016

Re: Mixed volume -> edge matrix is singular?

polymake uses the normalized volume convention for mixed volumes (i.e., counting solutions of polynomial systems directly, as in the BKK theorem). You can see this, e.g., from polytope > print mixed_volume(cube(2,0),cube(2,0)); 2 The mixed volume of a polygon with itself equals the volume (i.e., are...
by joswig
09 Aug 2021, 09:45
Forum: Helpdesk
Topic: how to avoid ERROR: No random access
Replies: 5
Views: 7167

Re: how to avoid ERROR: No random access

Well, Vector and Array are random access data structures, i.e., you can use indices. And Set is not random access; pretty much as the error message says. These different data structures exist because they help make several kinds of functions fast: While vector and Array allow to access an element at...
by joswig
31 Jul 2021, 18:44
Forum: Helpdesk
Topic: Label the ground set of a matroid from 1 to n
Replies: 3
Views: 6094

Re: Label the ground set of a matroid from 1 to n

Internally, polymake will always use indices starting at zero. matroid > $F = fano_matroid; matroid > print $F->CIRCUITS; {0 1 6} {0 2 5} {0 3 4} {1 2 3} {1 4 5} {2 4 6} {3 5 6} {0 1 2 4} {0 1 3 5} {0 2 3 6} {0 4 5 6} {1 2 5 6} {1 3 4 6} {2 3 4 5} But you can use LABELS to make things look different...

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