GAMS World Forum

Hermann, Your example is perfect for illustrating what compress is for. If I look at the domain info for your data, I see there is none: C:\support\mrw>gdxdump prices.gdx domaininfo SyNr Type DomInf Symbol 4 Par None AlP(*) 1 Par None DAP(*, *) 3 Par None PRLSP_Margin(*) 2 Par None PRLSP_Median(*) Y...

Luis, Looks like you found what you need, but another way to do this that is also helpful is to use a map. In the example below, the mapping set matches each element of n with a different i,j,k tuple. It sometimes help to dump the entire thing to GDX and browse it in the IDE: that really helps to se...

Hermann, To be precise, GAMS displays the linearization of the expression. Since you have multiplication, that linearization will involve the level values for some variables, but that's only because of the product rule for derivatives. If you have exp(2*x) + exp(3*y) =L= 10; you will not see anythin...

If you want to use CSV files with headers and not change them at all, you could use the GAMS utility csv2gdx. The datalib model csv2gdx1 gives you a working example: there's a call to csv2gdx in that model, and also some error checking. To read your file, I did: csv2gdx param.csv output=param.gdx ID...

We’ve received some user feedback recently that went like this: “I am confused. Rumor has it that the GAMS folks are working on a new IDE. Is GMS-Manager the new GAMS-supported IDE?” This is an important question that deserves a good answer. GMS-Manager is software developed by Ingo Huck and is dist...

Moosavi, I would not call the problem size you mention - 23k vars and 4k constraints - large-scale. If this is an LP, there is nothing remarkable about solving such a problem in seconds. You say it is a MIP, but you don't say how many of these 23k vars are discrete. And even if many are discrete, th...

Bilal, I tried out the search function within our documentation on our Web site (not the Web site search, but the search within the documentation) . I could search just within model libraries and found a nice example where the edist function is used in the the relief model: https://www.gams.com/late...

Have you had a chance to look over the rules for this forum (see the Rules tab)? It's good form to provide your name and affiliation. That increases the chance you'll get a helpful answer. In this case, divide and conquer is a good strategy. The first loop in the BASIC code computes L and Z, but it ...

Deepak, If you solve with a local solver, you get a local result, i.e. a result that satisfies local optimality conditions. The solver may not know your model is convex: in this case, it cannot say it is returning a global solution. The equation listing you mention is created by GAMS/Base before the...

It looks like there is an asterisk (i.e. a '*') in the first column of one of the lines defining your equations. In other columns, a '*' can mean multiplication, but in the first column, it indicates that this line is a comment.

-Steve