[Ipopt] ipopt in structural optimization

[Clausen Peter M.]

Hello

I am working at FE-DESIGN GmbH (www.fe-design.com) and our 
program TOSCA Structure is a structural optimization 
program. We use the Method of Moving Asymptotes (MMA of 
Krister Svanberg) as optimizer which in most cases does a 
really good job. In some cases though it has its drawbacks 
(linear object function, constraints which become active 
later in optimization) and we would like to test an 
alternative.

Our problems may exceed 1 mio. design variables and we 
usually only need around 30-50 iterations to converge. The 
primal solution is a FEM system solved by an external 
program, the sensitivity analysis (1. order) is done by 
ourselves. We have no 2. order information.

My questions:
1) How would you expect Ipopt to perform in a benchmark 
against MMA ? Has anybody got experiences?
2) We “warmstart” the optimization each iteration and 
leave the optimization to calculate the new primary 
solution. Thus we have changed the MMA so that we call it 
with objective function, constraints and sensitivities of 
the actual iteration plus some saved information from 
former iterations, e.g. the last asymptotes and other 
values. Could this be easily done with Ipopt ?

We would prefer to use the fortran version, but 
interfacing to C++ is nothing new to us. It would simply 
mean that Ipopt’s objects would be created and destroyed 
each iteration (would this be a performance problem?).

Best regards

Peter M. Clausen, developer at FE-DESIGN GmbH

_______________________________________________

  Peter M. Clausen

  Email: peter.clausen at fe-design.de
  Tel. : +49 721 96467 - 236
_______________________________________________

  FE-DESIGN GmbH, Haid-und-Neu-Str. 7, 76131 Karlsruhe, 
Germany
  Registration Court: D-Mannheim HRB 107382
  Director: Dr. Juergen Sauter
  Fax: +49 (0)721 96467-290
  Web: www.fe-design.com
_______________________________________________

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