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by opfer
29 Sep 2021, 20:00
Forum: General Discussion
Topic: how to define integer polytope by matrix representation
Replies: 6
Views: 279

Re: how to define integer polytope by matrix representation

I would like to add that it seems you forgot to add the bounds of your binary variables to the polytope. If you add them and then calculate the lattice points, you should observe only two integer feasible solutions. So your problem and its solution space is rather trivial.

Best regards,
Thomas
by opfer
02 Jun 2021, 19:54
Forum: Helpdesk
Topic: Issues solving an LP
Replies: 6
Views: 3971

Re: Issues solving an LP

Can you elaborate on how were you able to find the 240 feasible solutions/assignments for the integer variables? I used TOSimplex (one of the MILP codes in polymake) directly. It seems, polymake is currently not capable of doing this calculation. (It requires BOUNDED for the whole thing while for T...
by opfer
20 May 2021, 21:06
Forum: Helpdesk
Topic: Issues solving an LP
Replies: 6
Views: 3971

Re: Issues solving an LP

Please help me solve this MILP and find all the feasible solutions. It is typically impossiple to iterate all feasible solutions of a MILP, because if the remaining LP has several solutions for the same integer assignments, any convex combination is also feasible, yielding infinitely many solutions...
by opfer
09 Mar 2021, 23:20
Forum: Helpdesk
Topic: Error in reading a .lp file using lp2poly
Replies: 6
Views: 4403

Re: Error in reading a .lp file using lp2poly

If you use "simple" text editors (e.g. Notepad, Notepad++ on Windows or vi, vim, nano, mc on Linux or Mac), I would not expect any such problems.
by opfer
02 Mar 2021, 23:45
Forum: Helpdesk
Topic: Error in reading a .lp file using lp2poly
Replies: 6
Views: 4403

Re: Error in reading a .lp file using lp2poly

On my systems (Linux, Windows), the above command did not replace some strange white space character. I had to replace it manually.

Here is my corrected file:
untitled.lp
(2.12 KiB) Downloaded 154 times
I did a few tests with it. The optimal value is 7 and I found 880 feasible solutions.

Best regards,
Thomas
by opfer
06 Oct 2020, 09:59
Forum: Helpdesk
Topic: Simple question regarding converting polytope to facets
Replies: 3
Views: 3759

Re: Simple question regarding converting polytope to facets

It should be available through

Code: Select all

print $p->AFFINE_HULL;
Best regards,
Thomas
by opfer
28 Nov 2019, 17:10
Forum: Helpdesk
Topic: Error in using lp2poly
Replies: 21
Views: 9152

Re: Error in using lp2poly

TOSimplex can return all feasible solutions for the integer variables of a MILP, but this feature is missing in the interface to polymake You are cordially invited to extend the interface 8-) I think to do so, the MILP in polymake should somehow be extended. It seems to have no property like LATTIC...
by opfer
28 Nov 2019, 15:01
Forum: Helpdesk
Topic: Error in using lp2poly
Replies: 21
Views: 9152

Re: Error in using lp2poly

By the way, this feature seems to be missing in polymake. TOSimplex can return all feasible solutions for the integer variables of a MILP, but this feature is missing in the interface to polymake. In polymake, TOSimplex can only be used to obtain all lattice points of a polyhedron (which have to be ...
by opfer
27 Nov 2019, 20:53
Forum: Helpdesk
Topic: Error in using lp2poly
Replies: 21
Views: 9152

Re: Error in using lp2poly

Maybe, it is easier to feed polymake with these 125 points and let it calculate the inequalities and equalities from them. But I am really not sure about that.

Let's wait what the others say.

Best regards,
Thomas
by opfer
27 Nov 2019, 18:15
Forum: Helpdesk
Topic: Error in using lp2poly
Replies: 21
Views: 9152

Re: Error in using lp2poly

Hi UserCplex,

can you tell us, what the question is that you really want to anwer? Maybe, we need no projection to do so.

By the way, I used TOSimplex and found out that your problem has 125 different feasible solutions for the integer variables.

Best regards,
Thomas

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