[SCIP] SCIP and Pyomo

[Vladimir V. Voloshinov]

Dear Salva,

if there are no any discrete variables in your problem and you do not want
to treat it as a global optimization one, e.g. it is convex, or unimodal
(there is only one optimal solution), and local optimum will be enough for
you, then, you can use IPOPT "directly" from Pyomo. There is special
Pyomo-IPOPT interface...
But, frankly speaking, it is much more convenient to use IPOPT by the same
scheme: Pyomo->NL-file->IPOPT->SOL-file->Pyomo. E.g. you can generate
NL-files on your "small computer" and send them to a power server with
IPOPT (may be run in multi-threaded  mode on multi-core system) for solving
and return SOL-files  back for processing results via Python.

Vladimir.

On Mon, May 25, 2020 at 4:40 PM Salvador Pineda <spinedamorente at gmail.com>
wrote:

> Thanks a lot Vladimir,
> But then, what is the advantage of using IPOPT under SCIP with PYOMO
> versus using directly IPOPT in PYOMO?
> Salva.
>
> On Mon, May 25, 2020 at 2:35 PM Vladimir V. Voloshinov <
> vladimir.voloshinov at gmail.com> wrote:
>
>> Dear Salvador,
>> answering your questions (basing on our experience of SCIP usage) :
>> 1) Yes, SCIP does use IPOPT for NLP, but, theoretically other NLP-solvers
>> may be used via NLP API
>> <https://scip.zib.de/doc-7.0.0/html/group__NLPIS.php>
>> 2) Our team successfully use SCIPAMPL (AMPL-compatible SCIP-version) by
>> Pyomo: Pyomo makes AMPL NL-file as SCIPAMPL-input; SCIPAMPL returns AMPL
>> SOL-file as output; Pyomo reads SOL-file.
>> It is important that above scheme may be used for ParaSCIP & FiberSCIP
>> with some additional trick...
>>
>> Yours sincerely,
>> Vladimir V. Voloshinov, web: GoogleScholar profile
>> <https://scholar.google.ru/citations?hl=en&user=-m4QhNEAAAAJ&view_op=list_works&sortby=pubdate>
>>
>> On Mon, May 25, 2020 at 2:06 PM Salvador Pineda <salvapineda2 at gmail.com>
>> wrote:
>>
>>> Hi,
>>> I have a couple of questions regarding SCIP solver.
>>> 1) Does SCIP rely on other solvers such as IPOPT to solve non-linear
>>> optimization problems?
>>> 2) Can SCIP be used under PYOMO?
>>> Thanks a lot!
>>> Salva.
>>> _______________________________________________
>>> Scip mailing list
>>> Scip at zib.de
>>> https://listserv.zib.de/mailman/listinfo/scip
>>>
>>
>>
>
> --------------------------------------------------------------------------
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.zib.de/pipermail/scip/attachments/20200525/118bf4d3/attachment.html>