GAMS World Forum

Hi GAMS Users, We would like to announce the availability of the GAMS Beta Release 31.0.0. Please consult the beta release notes for details about new features and updated solvers: https://www.gams.com/beta/docs/RN_31.html If you are interested in experimenting with this beta release, please downloa...

Even if you remove constraints e6 and e7 (now the model becomes linear and can be solved as a MIP) the model is infeasible. So your claim that you got a solution (for this data) can't be true. Moreover, you only have max and sqr(G(t)) in your model. Due to your direction of your objective you can ch...

Without the data there is little help. Try a global solver for non-convex problems when you pay no attention to a starting point.

-Michael

Hi, 1) As Renger suggests you can call rm at run time via "execute 'rm -f nextcuts.gdx';". No need to first create a batch script. 2) The bchin.gdx in created when GAMS/CPLEX calls the usercutcall (via the gdx command line parameter). What you can do is to clear the data that is not releva...

It's unclear what np is, but I assume this is an alias to n. Posting complete examples really helps. Here are two solutions. One is a direct on and the other uses more symbols but can easily serve to calculate similar sums for other nodes, not just n4: set l /L1*L6/, n /n1*n5 /, t /t1/; alias (n,np)...

That's obviously a weird behavior. Without more information it is hard to say what's going on.

-Michael

Solvers work with tolerances. A popular tolerance for deciding if a value is "integer" is if abs(x-round(x))<1e-5. Many solvers allow you to change such tolerances. For example, Cplex: epint (see https://www.gams.com/latest/docs/S_CPLE ... CPLEXepint).

-Michael

I guess there is currently no other way than to create (utf-8 encoded) CSV file (from GAMS) and to load these into Excel. We (GAMS) has this on the radar and are working on this.

-Michael

Alternative optimal solutions? Both solutions have objective 2. So you get different (primal) solutions depending on pure chance. This is not uncommon. Just search the internet for "degenerate linear programs".

-Michael

Hi,

You need to understand the difference between compile and execution time in GAMS. See e.g. https://www.gams.com/latest/docs/UG_Gam ... ll_TwoPass. Creating a file at execution time is done via the put facility, see https://www.gams.com/latest/docs/UG_Put.html

-Michael