GAMS/convert solver

Problems with modeling
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abb.omidi
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GAMS/convert solver

Post by abb.omidi » 4 days ago

Dear community,

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

Code: Select all

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

Fred
Posts: 158
Joined: 2 years ago

Re: GAMS/convert solver

Post by Fred » 1 day ago

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

Code: Select all

*  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

abb.omidi
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Posts: 21
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Re: GAMS/convert solver

Post by abb.omidi » 15 hours ago

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

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