Can someone help me with GAMS Error 148 Topic is solved

Solver related questions
Post Reply
Bingo LI
User
User
Posts: 21
Joined: 5 years ago

Can someone help me with GAMS Error 148

Post 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
Attachments
Untitled_1.gms
(456 Bytes) Downloaded 310 times
User avatar
Renger
Posts: 639
Joined: 7 years ago

Re: Can someone help me with GAMS Error 148

Post 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
____________________________________
Enjoy modeling even more: Read my blog on modeling at The lazy economist
Bingo LI
User
User
Posts: 21
Joined: 5 years ago

Re: Can someone help me with GAMS Error 148

Post 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
User avatar
Gideon Kruseman
User
User
Posts: 24
Joined: 6 years ago

Re: Can someone help me with GAMS Error 148

Post by Gideon Kruseman »

Use the loop function.

Example in the attached file.

Gideon
Attachments
Untitled_2.gms
(678 Bytes) Downloaded 313 times
Gideon Kruseman
ex-ante and foresight lead @CIMMYT, big data focal point @CIMMYT, coordinator CoP socio-economic data @CGIAR_BigData
Bingo LI
User
User
Posts: 21
Joined: 5 years ago

Re: Can someone help me with GAMS Error 148

Post by Bingo LI »

It works
Thank you very much!!

Best,
Li
Post Reply