[MPI3 Fortran] Request for a straw vote.
Craig Rasmussen
crasmussen at newmexicoconsortium.org
Fri Jun 12 20:33:01 CDT 2009
On Jun 12, 2009, at 1:29 PM, Aleksandar Donev wrote:
> On Friday 12 June 2009 10:11, Craig Rasmussen wrote:
>
>> Drat, I thought copy-in/copy-out was solved. If the compiler does
>> copy-in/copy-out what does the dope vector look like? This will be
>> in a BIND(C) interface so I think the compiler should know it can't
>> control optimizations and shouldn't do copy-in/copy-out, it should
>> just pass the original dope vector.
> This is why it is important that the committee first really finalize
> the
> assumed type and rank stuff. We could do what you ask for, but I do
> not
> recall it being discussed. The latest unofficial draft from J3
> contains
> some comments, such as:
>
> [CER - add to last sentence]
> and copy-in/copy-out of the actual argument is prohibited.
>
> (who is CER?), which are not "official".
Oops, CER would be me. It looks like Bill didn't turn my comments
into official prose.
>
>
>> Since the C semantics don't allow for non-contiguous buffers, the MPI
>> standard could decide to say this is an error and have the MPI vendor
>> return an error condition.
> OK, got it.
>
> Yes, the MPI vendor should be allowed to flag an error, but only for
> the
> *non-blocking* versions. For the blocking ones, a copy can trivially
> be
> made, and should be done (it's the "Fortran" thing to do).
>
> Best,
> Aleks
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