[R] MC-Simulation with foreach: Some cores finish early

Markus Schmidberger schmidbe at in.tum.de
Tue Jul 12 14:03:48 CEST 2011

If you switch directly to the multicore package you can use the
mclapply() function. There, check for the parameter mc.preschedule=T /
F. You can use this parameter to improve the load balancing. 

I do not know a parameter to tune foreach with this parameter.


Am Dienstag, den 12.07.2011, 04:31 -0700 schrieb peter_petersen:
> Dear R-Users,
> I run a MC-Simulation using the the packages "foreach" and "doMC" on a
> PowerMac with 24 cores. There are roughly a hundred parametersets and I
> parallelized the program in a way, that each core computes one of these
> parametersets completely.
> The problem ist, that some parametersets take a lot longer to compute than
> others. After a while there are only a quarter of the cores still computing
> (their first parameterset), while others are already finished. But some
> parametersets are still untouched.
> I have thought about changing my parameterfile in a way, that every
> combination takes roughly the same time (longer computations are offset with
> less repetitions), but maybe there is a more elegant solution.
> "Is it somehow possible to wake the finished cores, while there is still
> work to do?" ;-)
> Sincerly,
> H. Bumann
> --
> View this message in context: http://r.789695.n4.nabble.com/MC-Simulation-with-foreach-Some-cores-finish-early-tp3661998p3661998.html
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