Could someone try running my MTSP problem

[Greg Netols]

Hi, i am a student at UIUC working on a Multiple traveling salesman problem. The number of constraints in my mod file exceeds the amount allowed on the student version, which i have installed on my pc. My university does have the full version of ampl installed on lab computers however it always fails with errors no matter how small of a problem i give it. So, i would greatly appreciate it if someone could try running the mod file and dat file that i have attached and reply back with if it worked and maybe a screen shot of the display of the x variable and objective function. Hopefully i can get my university to update / fix the current version of ampl in the current labs. 

Also when i scale down my current problem to below 500 constraints it runs on the student version. 

Thank you

[victor.z...@gmail.com]

You can submit your files to NEOS which is a free internet-based service for solving numerical optimization problems: http://www.neos-server.org/neos/solvers/index.html. Most NEOS solvers support AMPL input and there is no size limit.

HTH,

Victor

--
You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group.
To unsubscribe from this group and stop receiving emails from it, send an email to ampl+uns...@googlegroups.com.
To post to this group, send email to am...@googlegroups.com.
Visit this group at http://groups.google.com/group/ampl.
For more options, visit https://groups.google.com/d/optout.

[Robert Fourer]

You can solve your problem by sending your model and data files to the NEOS Server. The submission page is www.neos-server.org/neos/solvers/; scroll down to Mixed Integer Linear Programming and click on one of the AMPL Input links -- if you want to use one of the highest quality solvers, you can choose Gurobi or Xpress.

We do not have a record of installing AMPL on UIUC lab computers in recent years, so your lab may have an old version. The lab administrator can contact lice...@ampl.com for help upgrading the lab installation.

Bob Fourer
am...@googlegroups.com

=======

[Greg Netols]

Thanks this is excellent!

[Robert Fourer]

I don't see any solvers on NEOS that would handle logical constraints from AMPL (though the managers of NEOS could consider adding the free Gecode and JaCoP solvers described at http://ampl.com/resources/logic-and-constraint-programming-extensions/). However you don't need to use a logical constraint solver to handle the constraints in your model of the form

<ineq1> and <ineq2>

Instead you can just define two separate AMPL inequality constraints.

Bob Fourer
am...@googlegroups.com

=======

From: am...@googlegroups.com [mailto:am...@googlegroups.com] On Behalf Of Greg Netols

Sent: Thursday, February 26, 2015 1:02 PM
To: am...@googlegroups.com
Cc: 4...@ampl.com
Subject: Re: [AMPL 10092] Could someone try running my MTSP problem

I have changed my mod file slightly to now have several logical constraints. Are any of the NEOS solvers capable of logical constraints?