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Algebraic optimisation with OpenModelica

#108  Permalink Top

Algebraic optimisation with OpenModelica

Apr-07-10 18:40:11

Hi everyone!

My name is Petar and I am interested in applying OpenModelica to some process synthesis problems. I am very much impressed by the Modelica language itself, offering object orientation and equation modelling.

However, for the synthesis algorithm to work, I need to employ LP, NLP or a MILP solver, depending on the application. Could you please point some hints how to connect a solver - e.g. lp_solve?

#109  Permalink Top

Re: Algebraic optimisation with OpenModelica

Apr-08-10 03:35:03

Hi,

lp_solve is actually linked with OpenModelica. It is used for unit checking.
However, it could be complicated (if not imposible) to translate an usual Modelica model into an lp problem.
By default any Modelica model will be translated into a Hybrid DAE system. Have a look at the Modelica specification:
http://www.modelica.org/documents/ModelicaSpec32.pdf
As far as I can see you would need some sort of language extension to specify
minimization functions and maybe some new type of equations to specify constraints.
Then after the flattening you would have an lp problem that you could give to an LP solver.

You could also have a look at JModelica.org (http://www.jmodelica.org) as they are using an extension of Modelica called Optimica for optimization problems.

Cheers,
Adrian Pop/

#112  Permalink Top

Re: Algebraic optimisation with OpenModelica

Apr-09-10 12:52:42

Dear Adrian,

Many thanks for the answer. Indeed, you are right that there is also the language problem.

Petar

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