(j3.2006) (SC22WG5.4118) [ukfortran] Parallel random numbers
Thu Oct 22 14:22:40 EDT 2009
Here is some alternative wording. It says as little as possible, and most
of that is in a NOTE. I really do think that being too specific is a bad
mistake, as this is not an area that is easy to make proof against future
It is processor dependent whether RANDOM_SEED and RANDOM_NUMBER use
a common generator for all images or whether each image uses a
The range of possible implementations includes:
* All images use a common generator, and those procedures are
properly interlocked to make multiple calls in unordered segments
* Each image uses a separate copy of the same generator, with
the same or a different default seed for all images.
* Each image uses a different generator, possibly with true or
quasi-independence of those generators.
[ And, yes, if you have suitable hardware support, true independence
is possible. ]
Plus edits to A2.
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