[Coin-discuss] Open-source Modeling Languages

[Sebastian Nowozin]

Hello,

On Nov 20, 2007 5:35 PM, Kipp Martin <kipp.martin at chicagogsb.edu> wrote:

> > [...]
> > 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.

But then, the question of a natural and reasonably powerful
open-source modeling language becomes more pressing; having nice
intermediate problem format like OSiL/OSrL and cutting edge solvers
like Ipopt, CBC or Bonmin is not going to benefit a lot of users if
they cannot develop good models quickly in a language suited to the
task, at least not the non-programming users.

I have taken a look at FlopC++ and it looks really nice, especially
for going from a rapid prototype directly into a working component of
a software; but I find it hard to imagine it as standard form to
exchange/discuss/publish models in due to the compilation dependency.

(As one being not involved at all with COIN-OR and only from a user
perspective, so I'm sorry if I trip on anyone's toe.)  If one would
want to fill this gap, extending FlopC++ to support nonlinear
optimization might be one way to go, as it is already well integrated
with COIN.  Asking kindly the author of GLPK for relicensing of the
MathProg part of GLPK under the CPL and making it a larger subset of
AMPL would be another option; if the latter is done within OS, all
solvers who could read OSiL would profit from this in the future.

Sebastian