Hi Ronald, I'm from the CMPL team and I would like to analyze your problem. It could be - as mentioned by Xypron - a memory problem. Which version of CMPL do you use? Is it a binaries from the CMPL website or did you compile CMPL for your own? If so, did you compile it in 32 or 64 bit mode? Is it possible to send me your CMPL model? You can be sure that i would use it only for analyzing the problem.
Cheers Mike Am 25.11.2011 um 15:20 schrieb Ronald Wolthoff: > Thanks for your responses. Yes, GLPK is the solver and CMPL the preprocessor. > I meant that the increase in preprocessing time seemed steep relative to the > increase in solving time, but of course these are different processes, so > there is no obvious reason why they should behave in the same way. > Thanks for the hint on sparse problems and direct access to the library. That > seems promising and I will look into that. > >> Nigel Galloway November 25, 2011 8:32 AM >> Do you mean GLPK is Solver and CMPL is preprocessor? >> >> What do you mean by stronger than expected? What happens at 29 and 31. >> Draw a graph of times between 15 and 30. I would say that, if the graph >> is smooth then the value for 30 is exactly as expected. If its smooth to >> 29 then discontinuous to 30 it is unexpected. >> >> Andrew Makhorin November 24, 2011 4:11 PM >> -------- Forwarded Message -------- >> From: Ronald Wolthoff <[email protected]> >> To: [email protected] >> Subject: memory >> Date: Thu, 24 Nov 2011 09:44:57 -0500 >> >> Hello, >> >> I'm using GLPK in combination with CMPL and I encounter some issues with >> the time required for preprocessing. My problem has 2N^2 rows and 2N^4 >> columns (real variables, less than 1% non-zeros). When I run the problem >> for N=15 (450 rows, 101250 columns), the preprocessing takes >> approximately 1 minute and the solver 3 seconds, which is great. When I >> use N=30 instead (1800 rows, 1,620,000 columns) , the solving time goes >> up to a few minutes, which is still great, but the preprocessing time >> explodes to something like 9 hours. Although the problem is fairly >> large, this increase seems stronger than expected. Is there a way I >> could reduce the preprocessing time, e.g. by allocating more memory to >> the program? >> >> Many thanks, >> >> Ronald >> >> >> >> >> _______________________________________________ >> Help-glpk mailing list >> [email protected] >> https://lists.gnu.org/mailman/listinfo/help-glpk > _______________________________________________ > Help-glpk mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/help-glpk
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