endogenous relational operations require model type dnlp

Problems with modeling
yanzhiping
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endogenous relational operations require model type dnlp

Postby yanzhiping » 4 months ago

I was using convert.opt to write lp file in GAMS model. and I created a control parameter cntrflag(cntrpar) , 'convert' is included in the set cntrpar. I was able to run the following code previously.

But today when I rerun it, it threw out the error 57 and 256, that says
57 endogenous relational operations require model type dnlp
256 errors in analyzing solve statement

if(cntrflag('convert')=1,
Option mip = convert;
Mixplan.optfile = 1;
Solve Mixplan using mip minimizing objval;
);

I just cannot understand what's the problem with it since it worked well once.
Can anyone give me some ideas?

cladelpino
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Re: endogenous relational operations require model type dnlp

Postby cladelpino » 4 months ago

Most likely you have unwillingly introduced a syntax or conceptual error using conditionals involving Variables. (Perhaps a parameter which changed to a variable ?)

These are situations (I can tell from the top of my head, they may be more) where you would be prompted to switch the model to DNLP.

The piece of code you have discussed is correct and not the source of the error. The error is in one of the equations of the model. Check the line mentioned (57).

Good Luck !!!

yanzhiping
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Re: endogenous relational operations require model type dnlp

Postby yanzhiping » 4 months ago

Thanks. It is fixed. I introduced some parameters in the condition which made the problem non-linear I think.


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