[Coin-discuss] Open-source Modeling Languages

[John Pye]

Hi Kipp,

Kipp Martin wrote:
> Hi JP:
>>
>> I've done some preliminary work on linking ASCEND to IPOPT, but still
>> have a some work to do. Adding new solvers is quite straightforward in
>> general, but in the case of IPOPT I am having to do some work to provide
>> a sparse Hessian matrix calculation routine, and that still remains to
>> be done. And volunteers are very welcome, of course!
>
> We have a COIN-OR open source project, Optimization Services (OS),
>
> see
>
> http://projects.coin-or.org/OS
>
> that is designed, among other things, to hook modeling languages to
> solvers. They can be hooked using Web Services or locally on the same
> machine.

Thanks for alerting me to this. I've got a few questions, I hope that's
OK? You mention that OS can be used to hook modelling languages to
solvers. Can you detail what happens on the modelling-langauge end of
the hookup? Are symbolic equation structures transferred, or is it an
evaluation/callback type arrangement? What sort of API do you provide?
What modelling languages have been hooked up so far?

Also, is there any overlap between OS and the CAPE-OPEN optimisation
API? Is there a performance hit from encoding optimisation models using
XML? Are there plans to generalise the OS approach to other types of
problems such as ODE/DAE, NLA, etc (and how does OS mesh with other COIN
projects NLAPI and OSI)? Finally, is there provision for supplying
'external' equations/constraints/relations, for example embedded as
routines in DLLs?

I'd also alert you that your project is not listed here, which perhaps
it should be:
http://www.coin-or.org/projects/

Cheers
JP