Can someone help me with GAMS Error 148

GAMS
1

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
Untitled_1.gms (456 Bytes)

2

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)):

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/Mathematical_optimization#Multi-objective_optimization).
If you want to write an optimization problem, you have to write one objective function maximizing or minimizing one variable.
Cheers
Renger

3

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

4

Use the loop function.

Example in the attached file.

Gideon
Untitled_2.gms (678 Bytes)

5

It works
Thank you very much！！

Best,
Li