(j3.2006) (SC22WG5.4115) Parallel random numbers

Bill Long longb
Thu Oct 22 13:22:54 EDT 2009

Aleksandar Donev wrote:
> On 10/22/2009 4:52 AM, N.M. Maclaren wrote:
>> Specifying what is defined and what is not is very hard when
>> you need to allow for two different models. 
> Perhaps then we should pick one of the models, namely, the independent 
> sequence one.

Yes, I'm convinced this is the only practical option.

> What I believe we ought to do is provide the simplest model and not try 
> to do much:
> 1) All the sequencies are independent
> 2) The same random number generator is used on each image (same seed, 
> same sequence).

You want the "same default seed", right?  Each image should be able to 
independently change its own seed.

> 3) No restrictions on calling RANDOM_SEED and RANDOM_NUMBER ala ordering 
> of segments.

This approach is certainly the easiest to implement. It also makes the 
most sense when trying to write portable code.


Bill Long                                   longb at cray.com
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