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### Can someone help me with GAMS Error 148

Posted: **Mon Jun 24, 2019 10:08 am**

by **Bingo LI**

Hello all,

I have difficulties in solving my problem. Can someone help me with GAMS Error 148

Error Messages

148 Dimension different - The symbol is referenced with more/less

indices as declared

257 Solve statement not checked because of previous errors

Thank you,

Li

### Re: Can someone help me with GAMS Error 148

Posted: **Tue Jun 25, 2019 7:31 am**

by **Renger**

Hi

You are trying to find the minimum of the variable ETA which is defined over the set i using an optimization approach.

In your case, you could just find the minimum of sum(t,p_pvf(i,t)*c_pv(i)):

Code: Select all

```
parameter
mymin
;
mymin = smin(i, sum(t,p_pvf(i,t)*c_pv(i)));
```

In your formulation you have a i objective functions: you are trying to minimize each ETA instead of looking for the minimum of all ETA. Multi-

(take a look at

https://en.wikipedia.org/wiki/Mathemati ... timization).

If you want to write an optimization problem, you have to write one objective function maximizing or minimizing one variable.

Cheers

Renger

### Re: Can someone help me with GAMS Error 148

Posted: **Tue Jun 25, 2019 9:13 am**

by **Bingo LI**

Hi Renger,

Thanks for your answer.

In my purpose, I exactly want to minimize each ETA (ETA(1), ETA(2), ETA(3)) because I want to utilize some distributed algorithm. And p_pvf(i,t) is a variable in my future formulation.

Could you give me some advice to write it under the rule "write one objective function maximizing or minimizing one variable"?

Thank you!

Li

### Re: Can someone help me with GAMS Error 148

Posted: **Tue Jun 25, 2019 4:11 pm**

by **Gideon Kruseman**

Use the loop function.

Example in the attached file.

Gideon

### Re: Can someone help me with GAMS Error 148

Posted: **Wed Jun 26, 2019 12:58 am**

by **Bingo LI**

It works

Thank you very much！！

Best,

Li