[Coin-discuss] problems with OSL on Red Hat [was: AAP_BP example]

[Stephan Hennig]

Matthew Galati schrieb:

> [...]
> Adding a sanity check "isProof" should show that the return from OsiOsl's
> getDualRays returns a ray that is not a certificate. In my check I am using
> the following definition:
> 
>      p is a proof iff
>      Let z_j = u_j where p' A_j > 0
>              = l_j where p' A_j < 0
>      p'b - p'Az > 0
> 
> Using the (negative) of the return of OsiClp::getDualRays works fine. 
> Using the current return (or its negative) of OsiOsl and OsiCpx does not 
> provide a proof. Using the return of CPXdualfarkas also works fine - but 
> this is not currently implemented in OsiCpx. I might be implementing 
> something wrong - but that is my guess. For anyone that is interested, I 
> have some test cases where the isProof(OsiOsl/Cpx::getDualRays) = false.
> [...]

I think I got it. The wrong solution value on some problem instances and the
segfault are two independent issues. Because they appeared to me at once I
didn't separate them.

The segfault issue can be worked around by the two alternatives Laszlo posted.
The second still endures (and you accidentally discovered the same problem
with CPLEX yesterday). When I now read the other thread I must admit you
already stated that before.

Regards,
Stephan Hennig