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From: | Samik Raychaudhuri |
Subject: | Re: [Help-glpk] Solving a large LP problem |
Date: | Thu, 15 Jul 2004 11:03:12 -0400 |
User-agent: | Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040514 |
Hi Andrew, This is the output I got when I solved with a considerably smaller problem. ------------------------- $ glpsol --mps new.mps load_mps: reading LP data from `new.mps'... load_mps: name `BLANK' load_mps: 243742 rows load_mps: 364514 columns load_mps: 1148311 non-zeros load_mps: 1 right-hand side vector(s) load_mps: 0 range vector(s) load_mps: 0 bound vector(s) load_mps: 932145 cards were read lpx_simplex: original LP has 243742 rows, 364514 columns, 1148311 non-zeros lpx_simplex: presolved LP has 90344 rows, 203072 columns, 487180 non-zeros lpx_adv_basis: size of triangular part = 89732 umalloc: size = 3614184; malloc failed ------------------------------------Is this b/c I have less system memory available, or b/c of something to do with the code? How can I check if system memory is the problem.
Thanks very much for all your help. Regards, -Samik On 7/13/2004 1:43 PM, Andrew Makhorin wrote:
The last one I solved successfully had 1453 rows and 3200 cols before presolve in a MPS file. glpsol solved it like a snap.Do you mean that glpsol failed on other lp instances of moderate size (say, 2000 rows and 4000 cols)?I also have compiled the package from scratch with the latest source code on an AIX box using gcc 3.3.3.Any other thing you want me to check?Glpsol successfully solved big lp instances like yours (and even bigger), so I think it is some stupid bug. Ideally I need to know a point in glpsol.c where it crashes. You also can try `--nopresol' option. How big your mps file if it is gzipped? Can you make it available for downloading via ftp? Andrew Makhorin
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