[eclipse-clp-users] LP solvers via eplex

From: \ luke2k4_at_...6... <luke2k4_at_...6...>
Date: Tue, 13 Jul 2010 02:51:11 +0200
Dear ECLiPSe users,
I wanted to ask you about your experience with interfacing LP solvers
through the eplex lib.
I have been recently working on linear relaxation of a large industrial
problem ( more than half a million variables and and several tenths of
thousands of constraints), and I've cosen the ECLiPSe environment to model
the problem because it's good for fast prototyping. I've used the Coin-OR
CLP solver which is default in ECLiPSe. However I'd like to make some
performance tests with other solvers such as GLPK.

Sticking to the GLPK for a moment, if I understand it correctly, I would
have to build the GLPK with the Coin-OR OSI libraries added, to get a dll
which could  then be loaded by eplex ? I've seen that there is already an
entry in the eplex_lic_info.ecl for glpk, so provided that I have a glpk
library with osi I would have to uncomment the line, create a module
"eplex_osi_glpk.ecl" just like for the other solvers and than load ":-
lib(eplex_osi_glpk)" instead of ":- lib(eplex_osi_clpcbc)", please correct
me if I am wrong at some point.

Now moving to Express-MP, as far as I know this is commercial software from
"dash optimization", so I won't be able to use that with eplex unless I have
a valid license (the same case with CPLEX). What are than the libraries in
the \lib\ARCH\express1525 for ? At first I thought these are the complete LP
solver libraries because they are quite big, too big to contain only the
interface.

One more thing, when I run the Coin-OR CLP via eplex I get quite high memory
consumption ( up to 1GB ) which is understandable because the problem is
large. My question is does ECLiPSe limit in any way the memory usage of the
external solvers ? I would not like ECLiPSe to do that. I got the global
stack overflow a few times but i suppose that was because of large data
structures created while building the problem definition for the external
solver in eplex and not because of the Coin-OR CLP memory usage (no problems
after increasing the global stack to 0.7GB).

Thanks in advance for your help
Luke
Received on Tue Jul 13 2010 - 00:51:18 CEST

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