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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