Search found 19 matches

by silence
1 year ago
Forum: Syntax
Topic: Optimize reservoir hedging rules
Replies: 9
Views: 5372

Re: Optimize reservoir hedging rules

Silence, When I run your model with GAMS 39.2, I get this message in the log: CPLEX Error 5002: 'B_YNHpad3' is not convex. Looking at your GAMS source, I see equation B_YNHpad3: B_YNHpad3.. beg_S('Res_YNH')=l= Rule('1','YNH_pad')*Yp1('1')+Vupper('1','Res_YNH')*Yp2('1'); The multiplication of variab...
by silence
1 year ago
Forum: Syntax
Topic: Optimize reservoir hedging rules
Replies: 9
Views: 5372

Re: Optimize reservoir hedging rules

Can you explain why the model is miqcp? There is no quadratic term in the model.
Also, when solving miqcp with cplex solver, the error is reported as follows.
CPLEX Error 5002: 'QCP_row_for_B_YNHpad3' is not convex.
The latest code and input files are attached
Thank you very much for your help!
by silence
1 year ago
Forum: Syntax
Topic: Optimize reservoir hedging rules
Replies: 9
Views: 5372

Re: Optimize reservoir hedging rules

There are plenty of compilation errors in the code. I interpreted the error message you posted earlier incorrectly, I thought this was about order, but this was about an uncontrolled index used in ord. You seem to struggle with the concept of "parallel" statements in GAMS. You control ind...
by silence
1 year ago
Forum: Syntax
Topic: Optimize reservoir hedging rules
Replies: 9
Views: 5372

Re: Optimize reservoir hedging rules

The code you provide does not compile (because of other errors than you describe). Please provide a complete example that leads to your described problem. GAMS is not so intuitive when it comes to sorting since it maintains (due to efficiency) a single list of labels. If set membership goes against...
by silence
1 year ago
Forum: Syntax
Topic: Optimize reservoir hedging rules
Replies: 9
Views: 5372

Optimize reservoir hedging rules

Hey guys, We try to optimize the reservoir water supply hedging rule using a long series of runoff data. The rules take the form of reservoir storage corresponding to 24 periods of the year.When the initial reservoir storage is smaller than the corresponding time rule volume, the water supply is the...
by silence
2 years ago
Forum: API
Topic: Python API - mi.solve
Replies: 1
Views: 3504

Python API - mi.solve

Hi everyone, I’m using Python to call GAMS to solve an MIP problem. There are 6 parameters that need to be updated. When the model was run, the following problem occurred. 2.png When the parameters "COST" and "WD" were commented out, the model run successfully. 1.png What should ...
by silence
2 years ago
Forum: Solvers
Topic: Node limit exceeded. Set model attribute nodlim.
Replies: 4
Views: 4660

Re: Node limit exceeded. Set model attribute nodlim.

The results showed that there was an optimal solution What makes you think that you got an optimal solution? When I run the files that you attached (why use extension .txt for a GAMS source file???) all my solvers including the global solvers like BARON say that the model is infeasible. Nevertheles...
by silence
2 years ago
Forum: Solvers
Topic: Node limit exceeded. Set model attribute nodlim.
Replies: 4
Views: 4660

Re: Node limit exceeded. Set model attribute nodlim.

Here is my model and input files.
Thanks!
model.txt
INPUT.xls
by silence
2 years ago
Forum: Solvers
Topic: Node limit exceeded. Set model attribute nodlim.
Replies: 4
Views: 4660

Node limit exceeded. Set model attribute nodlim.

Hello, I have an MINLP model and intend to solve it with the SBB solver. The results showed that there was an optimal solution, but the output showed "Node limit exceeded. Set model attribute nodlim.". The results are all 0 in the .lst file and 0 in Excel. What should I do about this? Is t...