RE: [Help-glpk] memory problem solving a 4221 var and 1336 constraints

[Cheng,Jen-Min]

I had similar problem.  Windows Vista can only recognize about 3.5GB memory.
I recompiled glpk with Microsoft Visual Studio 2005 with /LARGEADDRESSAWARE.  
Call to WIN32 API GlobalMemoryStatus shows about 2.5GB is available to glpk.  
Similar message had been displayed when the "Memory used:" shows near 2 GB.

-----Original Message-----
From: address@hidden [mailto:address@hidden On Behalf Of Hernandez Florent
Sent: Wednesday, October 01, 2008 9:51 AM
To: address@hidden
Subject: [Help-glpk] memory problem solving a 4221 var and 1336 constraints

memory problem solving a 4221 var and 1336 constraintsI have a memory problem 
solving a simplex (real variables) with  4221 var and 1336 inequality 
constraints
The file written by glpk routine glp_write_lp() amounts to 140 MBytes.
When I read this file and try to solve it, memory usage climbs up to 1.5 Gbytes.
Then the malloc death sentence falls "umalloc: size = 8016; malloc failed ".

Why does my problem need so much RAM within glpk ?
I would expect far less.

When glpk reads the file, it says it has 1336 rows (correct), 8 910 531 columns 
(why?)
and 1 312 263 non zero values in the matrix.

Any help ?
Is it possible to handle glpk so that it minimises memory usage ?
Or should I think about another solver (which I don't want to!)

thanks,


Florent HERNANDEZ