[Scip] Inclusion/Use of SCIP through Sage

[Nathann Cohen]

Hello everybody !!!

I am new on this mailing list, and I have a question regarding SCIP's
license....

I am a contributor to the software Sagemath
(http://www.sagemath.org/), which is to be a Free alternative to
Maple/Matlab in Python. I am interested in Graph Theory, and I have
had to write in Sage a basic support for Linear Programming and Mixed
Integer LP, using GLPK, Coin (Cbc) and now CPLEX.

Some people among us found out instances for which SCIP is waayyyyyyy
more efficient (~700 seconds) than even CPLEX (crashed after 8 hours),
and we would like to be able to use SCIP through Sage. Well, it is
already possible to export the problem as a .lp file, then solve it
with SCIP, which is what we did until now, but it would be way better
if the use of SCIP was transparent...

Now, the thing is that Sage is GPL2, and can not include natively
softwares like GLPK (GPL3) or Coin (CPL). What we usually do is create
an optional package which is downloaded/installed independently by the
user, in such a way that it is automatically configured to work with
Sage. I would like very much to do this with SCIP, but I have yet to
know if I have the right to... It would mean shipping SCIP in a Sage
package, with some additional scripts to configure it. We have no
intention (and no interest) in modifying its source code.

As I read such things in the ZIB academic license, I think we clearly
qualify as a "academic use", most of the developpers being researchers
or student, and the whole thing being GPL2

Could you give me your advice on all this ?

Thank you very much for your help ! :-)

Nathann Cohen

( I mainly use LP in Sage to solve NP-complete problems in graphs like
Vertex/Edge-coloring (proper, but other ones too), Dominating set,
Integer Multiflows.... but also polynomial ones like Matching (
quicker to write a LP than Edmond's algorithm ), edge-artitions in
forests, orientations of graphs, etc... Sage's graph functions are
listed there http://bit.ly/a84bdH

Here is also an example of the use of LP in Sage : http://bit.ly/5o8teu )