[Coin-ipopt] Small problem to solver the big one...

[Arvind Uppili Raghunathan]

Hi Karsten,

  I have some prior experience in formulating optimal control problems in
AMPL and solving it using IPOPT. Usually things have worked or atleast I
have made them work. Let me know if I can help you in any way. You can
send me the mod files if you wish and I can get back to you with my
understanding.

  About AMPL not accepting the ipoptAMPL_options flag - I have had trouble
too. It seems like AMPL is not passing the flags correctly when invoking
the solver. You can also try the following,

 i) create a .nl file by issuing
    write gstub ;
 after you have loaded the model in AMPL.
 ii) run the model from command prompt as
     ipoptAMPL stub "imaxiter = 10000"
 This should work.

  Please let me know if I can be of any help.

Cheers
Arvind
>
> On Fri, 16 Apr 2004, Karsten Theissen wrote:
>
> > Hello again,
> >
> > I tested our ipopt-version with the programs Andreas told me. "of course it
> > worked...." So it seemed that something has to be wrong with my models (by
> > the way : AMPL and LOQO solved them without problems). So I write down the
> > easiest model (for solving optimal control problems with ODE's) that I can
> > imagine and  "of course it doesn't work". He told me that he reached the
> > iteration limit. So, now comes the small problem:
> >
> > Telling him:
> >
> > option ipoptAMPL_options "imaxiter = 10000";
> >
> > doesn't work. He ignores it.
> >
> > Can anybody tell me how I can write ipoptAMPL_options so that ipopt get it??
> > I only find the names of the options in the "Help-Readme-File" but not the
> > exact syntax (but maybe I'm blind).
> >
> > Thank you very much!
> >
> > Karsten
> >
> > P.S.: If anybody has solved discrete optimal control problems with ODE's or
> > PDE's with ipopt it would be nice if he can exchange some experience about
> > the ipoptAMPL options.
> >
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> >
> >
>
>
>