[Help-glpk] [Fwd: Determining memory requirements for a program and the best way to feed the program to glpsol]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Mehmet Yunt <address@hidden>
To: address@hidden
Subject: Determining memory requirements for a program and the best way
to feed the program to glpsol
Date: Tue, 27 Mar 2012 10:22:36 -0400

Hi

I am trying to solve a network problem where I have sources and sinks
only and the decision variables determine how the the flow from sources
is partitioned over the sinks. There are about 700K sources and 1K
sinks.  There are about 55 million non-zero variables.  There are
capacity constraints on the sources and requirements on the sinks
resulting in about 700K  constraints. 

I created a MathProg file describing the problem. I was not able to
process the file using 8GB of RAM.  GLPSOL v4.44  died while generating
caps because it ran out of memory.

I will need to reformulate the problem at hand, but the reformulation
will still have a  problem size with over a million variables.  

Nevertheless, I have the following questions:

a) Is there some formula to predict the amount of memory needed to solve
a problem for GLPSOL?

b) I plan to use the C API functions to solve a problem rather than
using a MathProg file.  Do the memory requirements change depending on
the way a problem is uploaded to GLPSOL?   


Regards

Mehmet