Questions tagged [ampl]

For questions related to the algebraic modeling language AMPL.

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6
votes
1answer
46 views

Issue interpreting sets of constraints in AMPL

I'm new to AMPL and am trying to model the following constraints. \begin{align}y_{ij3}&\le\sum_\ell X_{j\ell2}\quad(m=2,k=3)\\y_{ijk}&\le\sum_\ell\sum_mx_{j\ell m},\quad\forall i\in I,\forall ...
5
votes
2answers
85 views

Magic square in AMPL: presolve: constraint cannot hold [duplicate]

I'm solving the magic square problem without using the alldiff operator. To insert different values ​​in the matrix, I initialized a variable: ...
7
votes
2answers
88 views

Matrix in ampl: constraint that the values ​are all different

I'm solving the magic square problem for my operational research exam. The constraints of my model are that the sum of the elements on the lines must be equal to a constant (var constant), that the ...
8
votes
1answer
67 views

Understanding the AMPL Solver LIbrary within Pyomo

For anyone familiar with the Pyomo book, it occasionally makes reference to the AMPL Solver Library, and to my understanding, if you can manage to hook up to the solver library then you are able to ...
6
votes
1answer
95 views

Obtaining the intermediate solutions in AMPL

I know that for some solvers, for example, the constraint programming solver in Google OR-Tools, it is possible to see all the intermediate solutions that the solver finds while it searches for an ...
9
votes
1answer
116 views

Comparison of Algebraic modelling languages and general programming languages

Some optimization software/frameworks (commercial or open-source) such as AMPL, GAMS, Cplex, ... have a specific Algebraic modelling language. Some of them have another type of programming that uses ...
4
votes
1answer
53 views

Declare numerical-sequence set in AMPL .dat file

Suppose I want an AMPL set to contain the integers 1 through 5. How can I declare this in the .dat file? I can do it in the .mod file, like this: things.mod: ...