Search found 17 matches

by zar
3 years ago
Forum: Modeling
Topic: How to interpret BARON solutions
Replies: 2
Views: 3050

Re: How to interpret BARON solutions

Thank you very much Michael.
by zar
3 years ago
Forum: Modeling
Topic: How to interpret BARON solutions
Replies: 2
Views: 3050

How to interpret BARON solutions

Hi Everyone,

I solved my nlp model using BARON and got two different solutions, feasible and the best possible, please refer to below screenshot:
image.png
image.png (11.54 KiB) Viewed 3050 times
Among these two solutions, which one of them is the Global Optimal Solution?

Thanks
zar
by zar
3 years ago
Forum: Modeling
Topic: Can the value of Big M change my results?
Replies: 2
Views: 2091

Re: Can the value of Big M change my results?

Hi,

As per literature, you can use below equation in your model to find out value of bigM:
bigM = (x.UP - x.LO)*(y.UP - y.LO)

Regards,
ZAR
by zar
3 years ago
Forum: Modeling
Topic: Conditional variables
Replies: 4
Views: 3497

Re: Conditional variables

Hi Fred,

Can you help me with formulating the following function:
image.png
image.png (6.03 KiB) Viewed 2997 times
where, a(n) and a(n+1) are parameters, x and lambda(n) are variables.

Appreciate your help.

Thanks,
zar
by zar
3 years ago
Forum: Modeling
Topic: Linearisation of Bilinear Terms Using McCormick Envelopes
Replies: 1
Views: 2594

Linearisation of Bilinear Terms Using McCormick Envelopes

Hi Everyone, I am solving a problem by linearizing bilinear terms using McCormick envelopes. *NOTE: Equations are not written exactly as per standard GAMS syntex, so please ignore that and get the idea. *I want to linearize the following biliear term (EQ 1) using McCormick Envelopes: VARIABLES q, st...
by zar
3 years ago
Forum: Modeling
Topic: Using solution of one model as upper/lower bound in that model again - Global Optimization
Replies: 1
Views: 1557

Using solution of one model as upper/lower bound in that model again - Global Optimization

Hi everyone, I working on a global optimization problem, where I want to improve solution search space of the algorithm by using solution of local NLP solver as an upper/lower bound in the relaxed version of that model again. How can I achieve that: (a) By defining both models in the same file i.e a...
by zar
4 years ago
Forum: Syntax
Topic: Using Loop on Objective Function when the Looping Index is also Domain of a Table
Replies: 8
Views: 13091

Re: Using Loop on Objective Function when the Looping Index is also Domain of a Table

Hi Renger,

Thank you for your elaborate response. My problem is finally solved.

I owe you a Coca Cola :)

ZAR
by zar
4 years ago
Forum: Syntax
Topic: Using Loop on Objective Function when the Looping Index is also Domain of a Table
Replies: 8
Views: 13091

Re: Using Loop on Objective Function when the Looping Index is also Domain of a Table

Hi Renger, I appreciate your replies. Now, I defined my model parameters as below: PARAMETERS M 'Operating Mode' /A, B, C/ ratiomodel(p) / GO.A 0.1117 GO.B 0.1172 GO.C 0.1173 HN.A 0.0946 HN.B 0.0279 HN.C 0.0279 /; In the Loop, I defined the code as: LOOP(m, ratiomodel(p) = ratio(p,m); When I execute...
by zar
4 years ago
Forum: Syntax
Topic: Problem maximizing a infeasible function
Replies: 4
Views: 2943

Re: Problem maximizing a infeasible function

Hi,

According to my experience, this happens when there is a problem with model formulation. You may check the constraints and objective function.

Regards,
by zar
4 years ago
Forum: Syntax
Topic: Using Loop on Objective Function when the Looping Index is also Domain of a Table
Replies: 8
Views: 13091

Re: Using Loop on Objective Function when the Looping Index is also Domain of a Table

Hi Ranger, Thank you for your feedback. Are you suggesting to drop looping index(m) from the table as well? In the existing case, the table is 2-dimensional having looping index (m) on x-axis and liquid fractions (p) on y-axis. If I remove 'm' from the table then there will be a domain violation. Re...