Search found 8 matches
- 3 years ago
- Forum: Syntax
- Topic: Dynamic sets, set/domain assignment/violation problem
- Replies: 6
- Views: 7295
Re: Dynamic sets, set/domain assignment/violation problem
Steve, Yup, you're right. The initial formulation that I was working on was the transformation of a transshipment problem to a transportation problem. Like you said, the transshipment model based on Wikipedia's formulation is the actual linear programming model for the problem and this can be easily...
- 3 years ago
- Forum: Syntax
- Topic: Dynamic sets, set/domain assignment/violation problem
- Replies: 6
- Views: 7295
Re: Transshipment problem, dynamic sets, set/domain assignment/violation problem
Hi Renger, Thanks for the reply. I understood your approach well and knew where was I confused with assigning sets as subsets. However, the solution shows transshipment from same i to i (example: Brn to Brn). I need to model the objective function such that i is not equal to j in the second summatio...
- 3 years ago
- Forum: Syntax
- Topic: Dynamic sets, set/domain assignment/violation problem
- Replies: 6
- Views: 7295
Dynamic sets, set/domain assignment/violation problem
I'm trying to model a transshipment problem, the mathematical formulation of which is given in the picture attached. Transshipment model.PNG There are m supply centers and n demand centers, and X ij is the quantity shipped from center i to center j . Since in a transshipment problem, any supply or d...
- 5 years ago
- Forum: Modeling
- Topic: How to display decision variables in AUGMECON2?
- Replies: 4
- Views: 4654
Re: How to display decision variables in AUGMECON2?
Since I've been learning GAMS for only over two weeks now, I couldn't understand much of what you did with the codes in AUGMECON1. However, my question was more specific about AUGMECON2. I have a simple nature of bi-objective transportation problem for which I have modeled 'Model Definitions' (file ...
- 5 years ago
- Forum: Modeling
- Topic: How to display decision variables in AUGMECON2?
- Replies: 4
- Views: 4654
How to display decision variables in AUGMECON2?
The GAMS coding available for AUGMECON (1) and AUGMECON2 (2) display only the values of objective functions. I was wondering if it'd be possible to display the values of the decision variables in these methods, especially AUGMECON2. (1) https://www.gams.com/latest/gamslib_ml/libhtml/gamslib_epscm.ht...
- 5 years ago
- Forum: Modeling
- Topic: Problem with minimizing AUGMECON2
- Replies: 5
- Views: 4867
Re: Problem with minimizing AUGMECON2
If you could show me how that's done in this particular code, it'd really be a big help. I am a novice in coding. Tried a few here, but didn't work with setting the gridpoints to take integer.
- 5 years ago
- Forum: Modeling
- Topic: Problem with minimizing AUGMECON2
- Replies: 5
- Views: 4867
Re: Problem with minimizing AUGMECON2
I suggest reading the paper referenced in the header of the model to understand what is going on. Moreover, there is a parameter called dir in the original epscmmip model: Parameter dir(k) 'direction of the objective functions 1 for max and -1 for min' / k1 1, k2 1 / that allows the handling of dif...
- 5 years ago
- Forum: Modeling
- Topic: Problem with minimizing AUGMECON2
- Replies: 5
- Views: 4867
Problem with minimizing AUGMECON2
GAMS code for solving a multi-objective problem using the improved version of the augmented e-constraint method can be found here: https://www.gams.com/latest/gamslib_ml/libhtml/gamslib_epscmmip.html In this model, both objectives are used for maximization purpose. How do I convert this model for a ...