Hi Yanzhiping
You should look at the error message you get when you submit your model to gams.
It clearly states that it is expecting a '=E=', '=L=', or '=G=' in your equation. You have a '=', which is not allowed in equations (see the manual).
Cheers
Renger
sum over a set /p1*p5/ Topic is solved
Re: sum over a set /p1*p5/
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Enjoy modeling even more: Read my blog on modeling at The lazy economist
Enjoy modeling even more: Read my blog on modeling at The lazy economist