Re: [Help-glpk] interpretation of MPS files

[glpk xypron]

Hello Mike,

in glpk-4.45/src/glpmps01c you can find the following lines:

         else if (kind == GLP_IV)
            glp_set_col_bnds(csa->P, j, GLP_DB, 0.0, 1.0);

The GLPK default indeed seems to be an upper bound of 1.

lpsolve assumes an infinite upper bound, see
http://lpsolve.sourceforge.net/5.5/mps-format.htm

Same is true for Gurobi and ILOG CPLEX, see
http://www.gurobi.com/doc/40/refman/node580.html
http://www.lix.polytechnique.fr/~liberti/teaching/xct/cplex/reffileformatscplex.pdf

Hence I would consider the GLPK implementation as inconsistent with
the defacto standard for MPS files.

Best regards

Xypron

-------- Original-Nachricht --------
> Datum: Mon, 7 Mar 2011 15:37:13 +0100
> Betreff: [Help-glpk] interpretation of MPS files

> Hi,
> 
> I have seen that  the routines to handle MPS files were re-implemented in
> version 4.38.  
> According to these changes I found a different behavior in the
> interpretation of integers w/o upper bound. It seems that an integer w/o a 
> defined
> upper bound is interpreted as a binary variable. I guess that there is a new
> default value for a missing upper bound of an integer variable ( value of 1
> instead of infinity in the older versions). Am I right with these
> assumptions? 
> 
> Cheers,
> 
> Mike
> 
> 
> 
> _______________________________________________
> Help-glpk mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/help-glpk

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