[Help-glpk] slow matrix generation compared to AMPL

[Kendall Bailey]

Apologies if this is a duplicate... I evidently sent a mail with the 
wrong From:

  I received a .mod and .dat file from a colleague using AMPL, and 
tried to run glpsol --check on it.  I've added "data;" and "end;" 
statements where appropriate and everything worked fine.  The problem is 
that it took over 24 hours to complete, where AMPL takes 1 minute.  I'm 
not solving the LP, just reading the model and data.  The data file is 
about 82MB.  My hardware is comparable to his (1 GB memory), so I don't 
think its a case of excessive swapping.
The AMPL output says there are 262,048 constraints and 555,805 
variables.  Presolve with CPLEX eliminates 228,807 constraints and 
390,539 variables.  I'm not planning on trying to solve the LP with 
glpk, but thought about doing matrix generation (i.e. create an MPS file).

My question is whether it would pay to profile the code to find why it 
is so much slower than AMPL?  Could there be some poor memory management 
issue that is causing quadratic behavior (or worse) in the matrix 
generation phase?  Or is this more likely something very difficult to fix?

Thanks,
Kendall