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

[Andrew Makhorin]

> memory problem solving a 4221 var and 1336 constraints
> I 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.

Hmm... There is something wrong. How do you build your instance
before writing it with glp_write_lp? Are you using glpk api? Why do
you think it has 4221 columns, not 8 910 531 ones?

> 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!)