You can run the mps2gms utility (via some Java system call) to turn the MPS into a GAMS file. This GAMS file you can run with GAMSJob.run.
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- 3 days ago
- Forum: Announcements
- Topic: Job opportunity in the European Commission in Seville (Spain)
- Replies: 1
- Views: 126
New deadline: Deadline: 4 July 2019 23:59 Brussels time.
Yes, you can do that. Best thing to do it to have GAMS write to stdout (lo=3) and then you capture the log yourself. We do this in the OO-APIs. For example, in Python the GAMSJob.run method allows to pass in a textwriter that can be interrogated in a different thread.
Hmmm, unfortunately you did not show enough in the screen shot to see what file GAMS could not access. I guess this is "typical" virus scanner interference. The operating system is made believe the file access is freed but some process (the virus scanner) still holds on to the file and another proce...
- 5 days ago
- Forum: Tools
- Topic: Failure to change relative optimality error 1015
- Replies: 1
- Views: 51
This is a BARON internal message and it seems to indicate that changing a parameter with one of BARON's subsolvers resulted in some issues. I see that you are not using the latest version of GAMS an BARON. I suggested to run this with the latest version and see if the problem persists then please re...
Your expression is correct but it involves to minimize x which is hard when you try to just substitute |.| in a model. The absmip model (https://www.gams.com/latest/gamslib_ml/libhtml/gamslib_absmip.html) shows how to reformulate |.| with the help of a binary variable. You will need to have the some...
This has little to do with GAMS. Write down your MINLP with regular math constructs then the implementation in GAMS will be easy. Perhaps you should look into some modeling book (e.g. HP Williams, cited a lot by me in this forum). A short hint: have a set of selections set s / s1*s4 / with sizes par...
You can build up a set pos(p,x,a) that gives you the location a (in your vector) for the xth occurrence of the number p and with that you easily access the location of the ith location of a value. If you change c then the set pos becomes outdated and needs to be recalculated. So I you you just acces...
- 1 week ago
- Forum: Modeling
- Topic: Modeling of uncertainty through scenarios and storing in xlsx files
- Replies: 1
- Views: 143
If you look at the GDX file symbol sc generated by the gdxxw call you see what is going on (the set labels are your scenario parameters). You need to supply in Excel a column with scenario label names. I also had to modify the the gdxxrw command. The put_utility allows you to manage the writing of r...
Without further knowledge about the type of variables, the size of n etc it's hard to recommend anything. The constraints are nonlinear and while there are ways to linearize something like this (e.g. piecewise linear approximation) it's hard to suggest something useful without more details.