R devel - Nov 2012 - An idea: Extend mclapply's mc.set.seed with an initial seed value?

Hello,

Have been thinking that sometimes users may want each process to initialize
its random seed with a specific value rather then the current seed. This
could be keyed off depending whether mc.set.seed is logical, preserving the
current behaviour, or numerical, using the value in a call to set.seed.
Does this make sense?

If you wonder how I came up with the idea: I spent a couple of hours
debugging "unstable" results from parallel tuning of svms, which was
caused
by the parallel execution. In my case I can simply do the set.seed in the
FUN argument function, but that may not be always the case.

Ivan

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I appreciate your problem, and getting reproducible random generator 
results on a parallel system is something to be careful about. However, 
I would avoid making it too easy to have a fixed seed. In earlier days 
there were mistakes too often made by users inadvertently using the same 
seed over and over again (on simple single processor systems), for 
example, by reloading a session with the seed set.

Paul

On 12-11-01 08:46 PM, Ivan Popivanov wrote:
> Hello,
>
> Have been thinking that sometimes users may want each process to initialize
> its random seed with a specific value rather then the current seed. This
> could be keyed off depending whether mc.set.seed is logical, preserving the
> current behaviour, or numerical, using the value in a call to set.seed.
> Does this make sense?
>
> If you wonder how I came up with the idea: I spent a couple of hours
> debugging "unstable" results from parallel tuning of svms, which
was caused
> by the parallel execution. In my case I can simply do the set.seed in the
> FUN argument function, but that may not be always the case.
>
> Ivan
>
> 	[[alternative HTML version deleted]]
>
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