(j3.2006) (SC22WG5.4106) [ukfortran] Standard intrinsics and coarrays
Thu Oct 22 01:34:34 EDT 2009
Malcolm Cohen wrote:
> Aleksandar Donev wrote:
>> It is processor dependent whether all images use a common
>> generator or whether each image uses a separate one.
> Perhaps we should require that it should be one or the other.
If we require a single generator, it's difficult to get the same
sequence on a particular image on consecutive runs, which is useful
(some would say indispensible) for debogging, without specifying
rigorous synchronization, which might be more rigorous than the problem
If we require separate generators, one can get the effect of a single
generator by having one image do the generation. This might entail an
inolerable performance penalty.
It looks like Hobson's choice, but we ought either to choose, to provide
a mechanism for a program to choose, or require the processor to provide
a mechanism, outside the language, to choose.
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