Hello, 

I have a general question....

I implemented a mathematical model in AMPL, where I used CPLEX as a solver. I tested the model with many complex cases, and I always found a solution (after months of work in improving the model).

Now I wrote the same matematical model using OPL-CPLEX but I cannot find the same solutions as before (with AMPL-CPLEX) and in some cases I do find a solution but an order of magnitude worse, or even no solution at all...

Since the solver is the same in both cases, and the underlying mathematical model is the same, I expect to find the same solutions in both cases, or at least similar solutions...

Is it possible that I am not writing the mathematical model correctly in OPL?

Any idea?

Thank you

Samuele

Hi,

you should find equivalent solutions.

You could extract lp files and check them

regards

Hello, 

I have a general question....

I implemented a mathematical model in AMPL, where I used CPLEX as a solver. I tested the model with many complex cases, and I always found a solution (after months of work in improving the model).

Now I wrote the same matematical model using OPL-CPLEX but I cannot find the same solutions as before (with AMPL-CPLEX) and in some cases I do find a solution but an order of magnitude worse, or even no solution at all...

Since the solver is the same in both cases, and the underlying mathematical model is the same, I expect to find the same solutions in both cases, or at least similar solutions...

Is it possible that I am not writing the mathematical model correctly in OPL?

Any idea?

Thank you

Samuele