GAMS World Forum

You have implemented a semicont variable (https://www.gams.com/44/docs/UG_Languag ... sVariables). Many solvers do support them natively. But performance is usually comparable to your own binary reformulation (if your bigM is small enough).

-Michael

If each stock belongs exactly to one sector, you can change SC(s,i) to SC(i) because the sector is implicit for a given i. You can work with a map si(s,i) that tells GAMS about what stocks belong to what sector. In your algebra, you can use the map to access the sector (and it's data) if you iterate...

SBB itself dooes not do any scaling, but it runs NLP solvers to solve the relaxed model, these solvers, e.g. Conopt, will do scaling.

-Michael

I suggest you contact sales or support at gams.com. Too many things depend on you license and the forum won't be able to fix this.

-Michael

No, this is not possible. GAMSModelinstance only works with a fixed model rim. Sets change the model rim. The solution to this is to initiate the GAMSModelinstance with the full set of a possible subsets and use 0 (actually EPS) in the equation aalgebra (via some modifiable parameter) when you don't...

Hi, I don't know what you mean by this But now, having to write it professionally Almost all GAMS model have multiple indexes, this is as professional as it gets. There are ways to ""flatten" the index space, but that looks very ugly, so before suggesting ways to do this, I would like...

Since you haven't gotten any answer, I suggest to share the model to make this reproducible. -Michael

Rob, Studio adds a couple of parameters to the GAMS command line. Obviously, the last one pf="." is wrong. pf points to a GAMS parameter file with more command line options. Studio recently introduced the "GAMS Parameter File" feature, see https://www.gams.com/latest/docs/T_STUDI...

The steps that takes long is the extraction of the Q matrix from the non-linear instructions. There are basically two algorithms to do this and we default to the one (ThreePass) that is is fast in most cases. You might benefit from using the other algorithm (DoubleForward). We even have a "conc...

Hi GAMS Users, We would like to announce the availability of the GAMS Beta Release 44.0.0. Please consult the beta release notes for details about new features and updated solvers: https://www.gams.com/beta/docs/RN_44.html If you are interested in experimenting with this beta release, please downloa...