I just read again the link you provided before and I noticed there is a
posting that suggests a workaround to avoid the problem. I will do more
trials to see if it works properly. If it will not work, I will provide an
example of my model to investigate further.
For the moment, I really thank you for your help: I feel like your page
will solve my issue.
Thanks again.

--
Mattia Buccarella


On Fri, Jul 11, 2014 at 5:45 PM, Heinrich Schuchardt <xypron.g...@gmx.de>
wrote:

> Hello Mattia,
>
> please, provide an example model.
>
> Best regards
>
> Heinrich Schuchardt
>
> http://www.xypron.de
>
> Am 11.07.14 um 17:41 schrieb Mattia Buccarella
>
> > Thanks for your answer.
> >
> > The link you suggested is the one I already saw and discussed in my first
> >
> > email.
> >
> > My question is about the meaning of "constant", since all the terms in my
> >
> > objective function are functions of variables (i.e.: none of them is
> >
> > actually constant). Also, I would like to know if there is any way not to
> >
> > let this shift happen.
> >
> > Thank you again for your time.
> >
> >
> >
> > --
> >
> > Mattia Buccarella
> >
> >
> >
> >
> >
> > On Fri, Jul 11, 2014 at 5:35 PM, Heinrich Schuchardt <xypron.g...@gmx.de
> >
> >
> > wrote:
> >
> >
> >
> > > Hello Mattia,
> >
> > >
> >
> > > please, read
> >
> > >
> >
> > >
> http://en.wikibooks.org/wiki/GLPK/Troubleshooting#Objective_shift_term_ignored_when_exported
> >
> > >
> >
> > > Best regards
> >
> > >
> >
> > > Heinrich Schuchardt
> >
> > >
> >
> > > http://www.xypron.de
> >
> > >
> >
> > > Am 11.07.14 um 17:20 schrieb Mattia Buccarella
> >
> > >
> >
> > > > Hello everyone,
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > > > my name is Mattia and I am using glpsol in the development of my
> master
> >
> > > >
> >
> > > > thesis in computer science.
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > > > I am writing to you all for something I could not find anywhere so
> far.
> >
> > > >
> >
> > > > When I use glpsol to solve my model (written in MathProg, with
> separate
> >
> > > >
> >
> > > > data input file), all the variables are configured properly as I
> expect
> >
> > > (I
> >
> > > >
> >
> > > > am referring to a "dummy" input I use to verify the correctness of my
> >
> > > >
> >
> > > > model). Nevertheless, the value of the objective function is shifted
> and
> >
> > > I
> >
> > > >
> >
> > > > get the following message:
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > > > Model has been successfully generated
> >
> > > >
> >
> > > > *glp_mpl_build_prob: row obje; constant term 84384 ignored*
> >
> > > >
> >
> > > > GLPK Integer Optimizer, v4.52
> >
> > > >
> >
> > > > ...etc...
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > > > Searching the web, I found somebody had a similar issue but it was
> not
> >
> > > >
> >
> > > > related to the objective function and also involved CPLEX (context
> very
> >
> > > >
> >
> > > > different from mine). Does anybody of you know what is happening?
> When I
> >
> > > >
> >
> > > > try to solve the model (same model, same input) with COIN-OR Cbc,
> through
> >
> > > >
> >
> > > > AMPL, it gives me the non-shifted value. Also, it does not tell me
> >
> > > anything
> >
> > > >
> >
> > > > about constant terms in the function. Also, I checked again and
> again my
> >
> > > >
> >
> > > > objective function: all the terms are functions of some variable, so
> >
> > > >
> >
> > > > nothing is really constant in the calculation.
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > > > Thanks in advance for your help.
> >
> > > >
> >
> > > > Goodbye.
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > > > --
> >
> > > >
> >
> > > > Mattia Buccarella
> >
> > > >
> >
> > > > _______________________________________________
> >
> > > >
> >
> > > > Help-glpk mailing list
> >
> > > >
> >
> > > > Help-glpk@gnu.org
> >
> > > >
> >
> > > > https://lists.gnu.org/mailman/listinfo/help-glpk
> >
> > >
>
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