## Problem while modelling Pareto Optimal Solution

Problems with syntax of GAMS
Balu6667
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Posts: 4
Joined: 2 months ago

### Problem while modelling Pareto Optimal Solution

Respected Everyone, please check the below-attached code.

This is a multi-objective scheduling technique.
While optimizing the objectives separately, they are working fine, but when I tried to use Pareto optimal, I got constant optimized values instead of getting mutually varying values.
Please provide the error in case anyone finds it in the below attached and posted.
Untitled_8.gms
Pareto Optimal Problem

bussieck
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Posts: 933
Joined: 6 years ago

### Re: Problem while modelling Pareto Optimal Solution

Have you ever looked at the ranges parameter? I get:

Code: Select all

``````----    243 PARAMETER ranges
OF1min 625.394,    OF2max  35.830,    OF2min  35.830,    OF1max 625.394
``````
Not much wiggle room. When I try to explicitly min/max the two objectives via:

Code: Select all

``````solve problem using MINLP minimizing of1; ranges('OF1min') = of1.l;
solve problem using MINLP maximizing of1; ranges('OF1max') = of1.l;
solve problem using MINLP minimizing of2; ranges('OF2min') = of2.l;
solve problem using MINLP maximizing of2; ranges('OF2max') = of2.l;
``````
I get

Code: Select all

``````----    250 PARAMETER ranges
OF1min 625.394,    OF1max 985.626,    OF2min  35.830,    OF2max  35.830
``````
So not much room to get differences for OF2 and hence to point in doing multi-objective optimization. It's enough to min OF1.

-Michael

PS I used global MINLP solver BARON.

Balu6667
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Posts: 4
Joined: 2 months ago

### Re: Problem while modelling Pareto Optimal Solution

Respected sir,
As you have mentioned that there is no room for doing two objectives, I tried to make it into a single objective as coded in the below-attached files. but I am getting the error while doing so.

Sir, can you please resolve the issue and provide me with the path to get it for the below-attached codes (in between both the below codes I changed the formula of the previous code file's second objective ).

Untitled_12.gms
CODE-12
Attachments
Untitled_11.gms
CODE-11

bussieck
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Posts: 933
Joined: 6 years ago

### Re: Problem while modelling Pareto Optimal Solution

Sorry, no idea what you are asking for. I download both models. They both compile and solve fine. What do you think is the matter with them?

-Michael

Balu6667
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Posts: 4
Joined: 2 months ago

### Re: Problem while modelling Pareto Optimal Solution

respected sir,
while I was trying to optimize, it was showing.

DICOPT: Terminating
DICOPT: stopped on NLP worsening.

Balu6667
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Posts: 4
Joined: 2 months ago

### Re: Problem while modelling Pareto Optimal Solution

Respected sir,

For the above-attached codes (Untitled 11 and 12), when I was trying to optimize, it was showing the following errors.

DICOPT: Terminating
DICOPT: stopped on NLP worsening