R Parallel question

Hi All,

I have a question about R parallel computing by using snowfall.

How can I set the seeds on parallel workers to get the same result as
sequential mode?

For example:
sfSapply(c(1,1),rnorm)
[1]  1.823082 -2.222052
rnorm(2)
[1] -0.5179967 -1.0807196

How to get the identical result?

Thanks.
Libo Sun

Graduate Student,
Department of Statistics,
Colorado State University
Fort Collins, CO

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Hi All,

I have a question about R parallel computing by using snowfall.

How can I set the seeds on parallel workers to get the same result as
sequential mode?

For example:

sfSapply(c(1,1),rnorm)
[1]  1.823082 -2.222052
rnorm(2)
[1] -0.5179967 -1.0807196

How to get the identical result?
I don't think you easily can do it, since each node in a cluster has its 
own stream. Repoducing this on a different number of nodes would mean to 
jump around in the RNG stream whcih would be slow (and probably needs 
some programming work).

For a start, read ?RNG

Uwe Ligges
Thanks.
Libo Sun

Graduate Student,
Department of Statistics,
Colorado State University
Fort Collins, CO

--
View this message in context: http://r.789695.n4.nabble.com/R-Parallel-question-tp4380098p4380098.html
Sent from the R help mailing list archive at Nabble.com.

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