Hello Xypron,

Thank you very much. I will try both suggestions.

In principle, for variables I need: reduced costs, lower bounds and upper
bounds; and for constraints I need: dual values, lower bounds and upper
bounds.

Thank you again.

Regards,
Germán.


On Sat, May 1, 2010 at 2:12 AM, glpk xypron <[email protected]> wrote:

> Hello Germán,
>
> The GMPL language does not support suffixes.
>
> Some sensitity information is provided by
> glpsol --bounds filename
>
> Introducing suffixes to GLPK has been proposed before,
> but not implemented in the maintenance release.
>
> An unofficial patched version of a last year GLPK release can be
> checked out with subversion
>
> svn co http://glpk.dyndns.org/svn/glpk/branches/glpk-4.38-dot/
>
> It supports the following suffixes in the post solution phase:
>
> variables
> lb - lower bound
> ub - upper bound
> val - value
> dual - dual value
> basic - 1 if variable is basic
>
> constraints
> lb - lower bound
> ub - upper bound
> dual - dual value
> value - value
>
> You can use the suffix only on scalars:
>
> set S := {0..10};
> var x{S};
> ...
> #legal
> display x[3].lb;
> printf x[3].dual;
> #illegal
> display x.lb;
>
> To generate duals for MIP problems the integer variables are fixed
> and an extra call to the simplex routine is executed.
>
> It would be interesting to know which suffixes would be of most
> value for your use of GLPK.
>
> Best regards
>
> Xypron
>
> > I've a model in Mathprog which I'm solving using `glpsol` and using
> > `display` statements to generate a custom output. In AMPL there is a list
> > of
> > suffixes that one can use to display different properties of variables
> and
> > constraints. For example for a constraint the available suffixes are:
> >         astatus   body     defvar   dinit
> >         dinit0    dual     lb       lbs
> >         lbs1      lbs2     ldual    lslack
> >         no        relax    slack    sno
> >         sstatus   status   ub       ubs
> >         ubs1      ubs2     udual    uslack
> >
> > So, for example, you can write:
> >   display C.lb;
> >
> > To display the lower bound of C.
> >
> > Is there an equivalent functionality in Mathprog? The above syntax does
> > not
> > work.
> >
> > Thank you.
> >
> > Regards,
> > Germán.
>
> --
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>
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