Good evening, I am looking for a way to retrieve information from the final solve statement. Lower bound and Gap would be nice. I am working with the python api but i can only get the final obj. value and all parameters etc.. Is there a way to store the information I need in a parameter and what would be the command?

I want to access and store the underlined values in the picture..

enter image description here

  • $\begingroup$ Would you see .lst file in the GAMS directory? $\endgroup$
    – A.Omidi
    Commented Dec 15, 2020 at 7:16
  • $\begingroup$ yes i see the solution report in the .lst there but i need to automate the whole thing $\endgroup$
    – Eddiee
    Commented Dec 15, 2020 at 7:22
  • $\begingroup$ What you mean by automating the whole thing? When the problem is solved this file is generated automatically with the full reports. $\endgroup$
    – A.Omidi
    Commented Dec 15, 2020 at 8:15
  • $\begingroup$ I am solving multiple problems in a loop.. it's a bit tedious to get the data I want from the report $\endgroup$
    – Eddiee
    Commented Dec 15, 2020 at 10:59
  • $\begingroup$ UPDATE: my current workaround: use put Model.objest (this is what i found out how to get the lower bound) into a temporary.txt and access that via python kinda cumbersome but at least it works $\endgroup$
    – Eddiee
    Commented Dec 15, 2020 at 13:57

1 Answer 1


Collecting things in a parameter is actually very simple.

set run /.../;

parameter objresult(run,*);

    solve m ....
    objresult(run,"obj") = m.objval;
    objresult(run,"bestbound") = m.objest;
    objresult(run,"absgap") = abs(m.objval-m.objest);
  • $\begingroup$ will this parameter be in the .lst file? $\endgroup$
    – Eddiee
    Commented Dec 16, 2020 at 11:03
  • $\begingroup$ Otherwise i can't access it via the python api i think. Parameters which arent part of the actual model arent in the .lst? $\endgroup$
    – Eddiee
    Commented Dec 16, 2020 at 11:12
  • $\begingroup$ Sorry, I have no clue what you are saying here. The listing file is well just a listing file. I fail to see the connection with the Python API. This makes no sense. $\endgroup$ Commented Dec 16, 2020 at 11:45

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