GAMS World Forum

Tara got some help from GAMS support but I want to share some of our findings. First of all csv2gdx processes a single CSV file to create a single GDX file with a single parameter. So there is no batch processing in csv2gdx. Here are some other considerations when processing large CSV files. Python ...

Hmmm, there can be a few reasons why the loading of the names fails. First you might have disabled the generation of names inside the GAMS code. One can do this by setting mymodel.dictfile=0; before the solve statement (https://www.gams.com/latest/docs/userguides/mccarl/model_attributes_mainly_used_...

Hi, I don't know what kind of debugging you want to do but usually the equation listing in the listing file is a pretty good debugging tool if you visually need to inspect your constraints: A Transportation Problem (TRNSPORT,SEQ=1) Equation Listing SOLVE transport Using LP From line 66 ---- cost =E=...

Your analysis is correct. For other readers, this is only for the GAMS/Gurobi solver. Anyhow, in case of "MultiObj=1" the coefficients in the master objective "just" help to build the different priority classes. When I implemented this, I had in mind that I wanted to go easily fr...

Tiago, I agree that we should make sys12 more visible and give it a better name, but I also believe that this is a good default. Even global solvers benefit from a good starting point because they use local solvers for local search (e.g. BARON does a multi-start based on the initial point that hopef...

It does not matter where the basis (complete or incomplete) comes from. You just need to set (.l and) .m of your variables and equations. I did not get the experiment you tried to do in your attached GAMS model. To me it looks like that the second solve successfully restarted from a basis.

-Michael

This truly looks like a Cplex bug or numerical issue. If you add options writesav prob.sav writeparam param.prm to your GAMS/Cplex option file you could submit these two files together with the entire log to support@gams.com or directly to the Cplex folks. Please also provide information about the p...

Local NLP solvers need a good starting point to improve on. The starting point you provide (0,0) can't be evaluated and hence the solver could not compute a direction that improves the situation. Hence GAMS checks if the starting point can be calculated. If not, GAMS will not pass the model to the s...

The problem is that GAMS waits for the user to react on the "Terminate batch job (Y/N)?". With older OS versions this was not a problem but it surfaced eventually. Anyhow, a newer GAMS version (>=24.0) fixes this problem (see http://www.gams.com/latest/docs/releasenotes/24.0.html#gams). Yo...

Leo,

The key GAMS/Cplex option for LP restarts is 'advind' (http://www.gams.com/latest/docs/solvers ... PLEXadvind). Perhaps you can post some logs or even share your model and starting point, so we have more to go on.

-Michael