[Coin-discuss] Open-source Modeling Languages

[Kipp Martin]

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