Using external solvers

DEPS Studio can be used to export a compiled DEPS problem model to external solvers if needed. Models can be exported directly after compilation, or after a narrowing phase to obtain reduced bounds on the domains of problem variables.

In addition to the solver integrated into DEPS Studio, various existing external solvers can be used for performing dedicated resolutions: linear programming (LP, MILP, ..), non-linear mathematical optimization (MINLP, …), metaheuristics, etc.

There are two possible ways to build such a bridge:

  • Using a flat problem modeling language

  • Using an optimization library and a programming language

../_images/FlatModelsExternalSolvers.png

Using a flat modeling language

Several languages are available for modeling flat problems. They propose to represent the problem in the form of a set of variables and a set of equations and inequalities, possibly with an objective function to be optimized. Flat modeling did that and are connected to several solvers. In DEPS Studio it is possible to generate a flat model for such langages from a structured DEPS Problem model.The flat models thus generated can then be solved by various existing solvers. As an example, flat models in languages as AMPL and MiniZinc can be generated form DEPS Studio.

Some other flat modeling languages are dedicated to a specific solver.

Using a library

Some solvers are available as libraries from a programming language such as C++, Julia or Python. Some examples include JuMP for Julia or Pyomo for Python. To use them, you need to write a program in the dedicated programming language. With DEPS Studio, you can generate automatically code in a given programming language and then use the dedicated optimization libraries.

If you would like to know more about these aspects, please contact us.