[Coin-discuss] Open-source Modeling Languages
Kipp Martin
kipp.martin at chicagogsb.edu
Tue Nov 20 11:35:05 EST 2007
Hi Ted:
>
> As I understand it (from my outside viewpoint as a user), the intention
> is not for most normal users to ever actually write code to produce a
> file in XML format. The XML format provides a standard low-level
> interface to a wide range of solvers (something that didn't previously
> exist), but in most cases, users would use a higher-level layer (such as
> a modeling language or something like the current Osi) that would
> actually produce the XML. Most users probably wouldn't ever see the XML.
> The OS folks can correct me if I'm wrong, but it seems that the XML file
> acts more like the .nl file that AMPL produces (as an intermediate
> format between AMPL and a solver) than an MPS file. I doubt most people
> have ever looked at a .nl file. It is produced transparently by a higher
> level layer and they never see it.
Exactly! OSiL is a representation for an instance as opposed to the
higher level model. We don't expect people to really look at an OSiL
file. But if they did I think it would be a lot more transparent then nl
or mps.
>
> The bottom line is that all this should be transparent for most users.
> Even with the OS framework, it should still be easy to input files in
> MPS format in the same way as it is done today by, for instance, reading
> the MPS file into an Osi object and then using the OS framework's back
> end to Osi to write out the XML (although I don't know exactly why
> anyone would want to do this). You can provide any sort of high level
> interface you want. It's just that some back end has to eventually
> produce the XML to be handed to the OS interface to the solver. Of
> course, not all the pieces are in place to make this a reality, but by
> defining a standard, the OS project has at least provided a starting
> point to develop a wide range of interoperable high level interfaces.
> After that, the sky is the limit. OS folks, is this correct?
>
100 percent correct and stated more clearly than I have ever stated it!
Thanks
--
Kipp Martin
Professor of Operations Research
and Computing Technology
Graduate School of Business
University of Chicago
5807 South Woodlawn Avenue
Chicago, IL 60637
773-702-7456
kipp.martin at chicagogsb.edu
http://gsbkip.chicagogsb.edu
http://www.coin-or.org
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