[Cbc] Infeasible only with Multithreading

[John Forrest]

Mario,

Multi-threading comes in two flavours - opportunistic and deterministic.

Opportunistic is more efficient, but not exactly repeatable.

The meaning of the parameter threads is -

0 - off - running in serial mode
n (1-reasonable) - opportunistic using n threads.  With k cpus, I would 
use k or maybe one more.
n (101-) - deterministic using n-100 threads.  With k cpus I would use k 
or maybe up to 2*k as load balancing is worse.

threads == 100 ! should be as 0, but somewhere a parallel flag has been 
set and so things go wrong.

Solution - don't use 100 - I will probably get round to treating as 0.

John Forrest
On 29/12/14 16:36, Mario Souto wrote:
> Dear all,
>
> I am using the version 2.8.12 of Cbc and having some strange problem 
> with the Multithreading feature. The following problem is 'proven 
> infeasible' when using 100 threads. However, an integer solution cab 
> be found when only one thread is used.
>
> Does any one have some idea about it?
>
> Thanks in advance,
>
> Mario Souto.
>
>
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