Re: [Help-glpk] Solving a large LP problem

[Samik Raychaudhuri]

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
>
>
>