On Friday, December 27, 2013, Reginald Beardsley wrote:
Nazmul,
I suggest you consider using awk to generate data files in GMPL format from ASCII text (.txt) files if you have very many instances to solve. You put the problem formulation in one file and the data for each instance in another file and execute "gplsol -m model.dat -d data.dat". I've found this works very well solving large numbers of problem instances. In particular, it makes changing the model very simple. I can't find out anything about the Guesk editor so I can't comment on setting up GMPL notation data files using that.
I tried using the CSV import facility in GMPL, but found it not very convenient because of restrictions on the CSV format glpk accepts.
There is a MATLAB binding for GLPK, but I don't know how usable it is. The MATLAB clone, Octave, also has a built-in binding to GLPK.
http://en.wikibooks.org/wiki/GLPK/Matlab
http://en.wikibooks.org/wiki/GLPK/Octave
http://en.wikibooks.org/wiki/GLPK/Scripting_plus_MathProg
There is a Gnu implementation of awk, gawk, which is standard on Linux systems. It's also available on Windows.
http://gnuwin32.sourceforge.net/packages/gawk.htm
If you need help with writing an awk script to convert the MATLAB .txt files to GMPL notation send me a small example of the MATLAB .txt file and I'll add an example to the GLPK wiki.
You'll need to figure out how to write a basic GMPL problem first. A good place to look is in the examples directory at cf12a.mod which implements an L1 line fit. I solve physics inverse problems by basis pursuit using GMPL notation so I can probably offer some help. I do problems with 30,000 columns by 50-300 rows. The resulting files are huge, so you want to get everything working using a small example before doing something that large. I did some little 10x10 problems to figure out how to set it up.
Reg
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On Thu, 12/26/13, Nazmul Islam <address@hidden> wrote:
Subject: [Help-glpk] Import data from Matlab variables to GLPK/GMPL
To: address@hidden
Date: Thursday, December 26, 2013, 8:49 PM
Hello,
I want to write my GLPK code through the Guesk
editor and I am very new to the GNU Math Programming
Language.
I want to import some data from Matlab to my GLPK
code. I want to run the code with these imported data. The
data is currently in some variables of Matlab and I can
store them in some .mat files. Do I need to save all these
Matlab variables in a single .dat file (or .txt file?) and
then import to GNU Math Prog language?
Is there any example that I can
follow?
Thanks,
Nazmul
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