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Re: [Help-glpk] gmpl manual


From: Brady Hunsaker
Subject: Re: [Help-glpk] gmpl manual
Date: Thu, 20 Mar 2008 23:41:24 -0400
User-agent: Icedove 1.5.0.8 (X11/20061123)

Guney Petek wrote:
On Wed, Mar 19, 2008 at 4:09 AM, Andrew Makhorin <address@hidden> wrote:

I read that "... the mathprog translator is greedy to the memory
..." and actually I am having problem getting the model generated for
a large instance. glpsol runs out of memory on a machine with 1.5GB of
memory before half of the constraints are generated.
GLPK implementation of the MathProg language is not very efficient,
so huge models cannot be processed by the translator.

One reason I am
learning GMPL is to be able to use GLPK. Would you recommend me an
other language in that case?
Which language do you mean? Programming language or modeling one?


I was asking about modeling languages for LP,IP,MIP. Let me rephrase my
question: In order to use the highest number of GPL or open source solvers
out there which modeling language would you people recommend learning?

I thought GMPL/AMPL was the best choice however, what is the path, then, to
follow in order to translate huge models to mps?

I use Java  Programming language to create my mod/dat files. Would it be
best if I learn the MPS format itself and author my instances directly into
MPS? How doable is this for a human being? Could you please give me some
more insight as to what the alternatives might be?

Thank you,
Guney


For modeling language tools, there are few that are free software. GMPL is a good choice. The other two that I know of off-hard are FLOPC++ (based in C++) and PuLP (based in Python). I haven't used either of these personally.

In general I don't recommend generating instance files like MPS or CPLEX LP directly. If you don't want to use a modeling language because of size or other issues, then look at the APIs that solvers have to directly input an instance. COIN-OR OSI (Open Solver Interface) provides an API that can interface with a number of solvers, including GLPK and CLP (both free software).

Brady




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