Closed yuandong-tian closed 2 years ago
Hi @yuandong-tian,
We did make a change in the SetCoverGenrator
in version 0.8.0 in #301, but it should only change the objective, not the constraints.
It would be worth testing this with Ecole 0.8.0 and Scip 7
Can you reproduce you example with a fixed seed (.i.e making it deterministic for us).
Thanks @AntoinePrv for answering. It doesn't seem to be related to random seed. So any seed should just have the same issues. Also how to install Ecole 0.8.0 with SCIP 7?
@yuandong-tian, using Ecole 0.8 + pyscipopt 4.0 + SCIP 8.0, and running your example about ten times, I only got feasible instances (reading optimal
).
Hi all,
@yuandong-tian I don't think you can install Ecole 0.8 with SCIP 7. I think @AntoinePrv meant SCIP 8.
I've tried also your minimal program on my side with both Ecole 0.7.3 and Ecole 0.8.0, I can't reproduce the issue. Given the weird numerical value you get in the constraint, my bet would be for a numerical rounding that occurred somewhere during the instance generation process. That's annoying, but since we can't reproduce it's hard to look into it. @yuandong-tian could you give us additional info about the machine you ran the code on ? Maybe also the python version, the version of the numpy library etc. ? If you're using conda, a conda list
should give you that.
Best, Maxime
Minimal program:
In Ecole 0.8 + pyscipopt 4.0 + SCIP 8.0, it gives
In Ecole 0.7.3 + SCIP 7.0.3 + pyscipopt 3.2.2, it gives
Saving to .cip shows that there is a weird constraint in the generated program specification.
Maybe SCIP Infinity is converted to 2.12199579145934e-314 (or a memory overflow error).