Re: [Help-glpk] Out of memory, malloc error

[Andrew Makhorin]

> We have a (what I consider) to be fairly simple model, which performs
> very well for small - medium data sets (between 500 and 2500 lines of
> data).  However, we recently tried to use the mod file for a larger data
> set (about 3200 lines of data).  Note: We're not using glpk to solve our
> Integer Program, we use it to create an MPS file, which is then solved
> by another solver, so we use the --check option.  Using this method, we
> have an MPS file generated in under 20 seconds.

> Using a faster Core 2 Duo, 2GB of RAM, and 2GB of swap, glpk ran fine
> until our last rule.  In the last rule, memory sky rocketed from 400MB
> for the glpk process to more than 4GB, resulting in a system load of
> over 20, and glpk eventually quit with a malloc() error.  It took over
> 60 minutes to get to this point.

> So, I moved it to our production system, which has 4GB of RAM and 4GB of
> swap, and the same thing occurred.  It took over 40 minutes to get to
> this point.

> Our original data sets use about 200 - 300MB, in total.

> Any ideas on how we might go about speeding up the creation of the MPS
> file .... and bringing down the memory footprint?

Most probably this happens due to huge amount of data, because
internal model representation used in the MathProg translator has
relatively high overhead expenses.

Is there an excessive swapping on the generation phase?

Which is the model size (estimated) for successful and unsuccessful
runs, resp.?