Re: [Help-glpk] GLPK Maximum row limit error

[Andrew Makhorin]

> I am using GLPK to create an LP file which I will later optimize using
> CPLEX. 
> But while I am creating the LP file, the following error occurs.
> #####
> glp_add_rows: nrs = 186919944; too many rows
> error detected in file ..\src\glpapi01.c  at  line  251
> #####
> 
> 
> I checked the resepectiv .C file and found that GLPK has a row limit
> of 100000000. Can this limit be changed ? 
> Could you help me with a way around this issue ?
> For the back ground. This model is a energy systems model on the likes
> of MARKAL in open source. This problem occurs when I am trying to
> model the whole of Africa's energy system (more than 10 countries at a
> time). My GNU Mathprog code is 470 line long and my data file is
> 1000000 lines long.
> 

This limit is used to prevent possible integer overflow, because to
access array elements glpk routines use indices of the 'int' type, which
are 32-bit signed integers (on both 32- and 64-bit platforms).

You may try to increase this limit, say, to 2*10^8, as well as other
limits on the number of columns and non-zero constraint coefficients.
However please note that the glpk itself is not intended to solve such
huge models.