[Coin-discuss] GMPL support in COIN-OR

[Michal Kaut]

 > What I think is happening is that Cbc uses libglpk only to read in and
 > build the model, but does not have access or does not use anything that
 > comes after the solve command.

It looks like it. (Actually, I have not managed to get the solution out 
of the standalone cbc solver at all, but that is a different issue..)

The interesting thing is that Symphony not only has access to the 
solution, but also to the variable names and indices, as it prints all 
non-zero variables with their GMPL notation.
And since it has processing routines for the printf commands (both 
Symphony and cbc can process commands prior to the solve command), there 
just might be a way of getting the output using the current glpk library 
after all .. but I guess this is a question for the Symphony mail-list?


 > It would be really nice to have that feature (executing the commands
 > after solving).  In the long run, it would be even nicer to have the GNU
 > MathProg part factored out of GLPK into its own library under a COIN-OR
 > compatible license such that many solvers can access it directly.  But
 > this of course is up to the GLPK author, license-wise, and there are
 > many valid reasons to have it licensed under GPL-only.

Would be nice, esp. since one could add non-linear support .. but, as 
you have said, there is not much we can do about it.

Michal