Explicitly provide supported versions of Cbc

[chrissype]

The packaged Cbc binaries are quite old (2 years). So I've built my own more modern version of Cbc using coinbrew, which sort of works. But Cbc behaves variously in strange ways, some of which are documented in other issues here. Would it be possible perhaps to provide explicitly supported versions (or even just commits on master) of Cbc, so that we can be sure the binaries we build are compatible?

[chrissype]

anyone?

[tkralphs]

What do you mean by "compatible"? And what do you mean by a "more modern version of Cbc"? Do you mean the tip of the master branch? Since two years ago (actually, since quite a few years ago), not very much has changed in master that would affect performance, other than refactoring, which was not supposed to have affected anything algorithmic at all. As it turned out, it did in fact affect execution is some subtle ways because of unintended changes in the way default parameters are set.

Can you give an example of what you mean by Cbc behaving "variously in strange ways." @h-g-s can correct me, but I believe python-mip was developed natively for Cbc master, which at the time had the same API as 2.10. There were some bugs introduced when the refactor branch was merged in master, but I think those have been fixed. If the weirdness you're referring to is about performance, you could try the latest release, which may exhibit less performance variability.

In any case, if you provide more details, I/we can probably advise. Someone else (@h-g-s ?) can jump in and correct me, but I don't think the master version of Cbc has been particularly well-tuned across a wide variety of problems. My impression is that the added methodological elements were tuned to work well on specific classes of difficult problems, so performance may be more variable than the releases.

[JoOkuma]

Hi @tkralphs, could you provide more details on this?
I'm trying to build Cbc from with today's master using the bash scripts from this repo's scripts,, but I'm having trouble with libCbcSolve, which doesn't seem to exist anymore.

[tkralphs]

I don't think what you're asking is related to this issue per se, but to give a partial answer, yes, libCbcSolve was merged with libCbc in some refactoring that took place a few years back. There was no real purpose to having separate libraries. I'm not a maintainer here and I'm not sure if python-mip was ever adapted to work with the latest commit in master, but I recall that someone had overcome this issue. Take a look at #276.

[JoOkuma]

thanks @tkralphs , I was able to fix the build scripts, they are not up to date as you said

Removing their respective -l... flag worked.