GAMS/convert solver

GAMS
1

Dear community,

I have tried to use convert facility to write a (.MPS) file from an NLP solver. The code is as follows:

model Mark_cut / all /;
*** Modifications
* choose convert as solver
option nlp = convert;
** write convert option file
$echo fixedmps Mark_cut.mps > convert.opt
** instruct convert to look for a solver option file
Mark_cut.optfile = 1;
solve Mark_cut using nlp max obj;

While I run the model I get a (.MPS) file that, it does not work.
Would you please, say that does convert facility do that? If so, how can I fix it?

Regards
Omidi. A

2

Hi,

MPS is a file format for linear problems: https://en.wikipedia.org/wiki/MPS_(format)
If you look into the resulting mps file, you should see hints like

*  Cannot handle NLP
[...]
*  Cannot handle nonlinear equations, nonlinear part ignored.
*  Cannot handle nonlinear equations, nonlinear part ignored.
*  Cannot handle nonlinear equations, nonlinear part ignored.
[...]

I hope this helps!

Fred

3

Dear Fred,

Thanks so much for your reply. Would you say, is there any way to get a (.MPS) like format from GAMS, please?

Regards
Abbas