[MPI3 Fortran] Non-contiguous arrays (was Re: Argument data sizes)

[Craig Rasmussen]

On Sep 18, 2008, at 11:40 AM, Aleksandar Donev wrote:

> On Thursday 18 September 2008 10:28, Iain Bason wrote:
>
>> Didn't this come up in another thread?
> Yes :-)
>> In Fortran, you can use
>> assumed shape arrays to pass these sorts of data without copying.  It
>> would be nice if MPI could take advantage of that in order to make
>> life easier for Fortran programmers.
> It can, after we publish the Interop TR currently being worked on by  
> J3. It
> would allow for declarations such as:
>
> TYPE(*), DIMENSION(..) :: buffer
>
> which would pass an array descriptor for buffer that can then be  
> parsed even
> by third-party libraries and a copy avoided. This would, however, as  
> Jeff
> said, be new *functionality* that we would be adding on top of the  
> base MPI
> standard. As such, it should probably be in addition or on top of  
> the basic
> Fortran binding which merely translates the MPI standard.

Jeff Squyres and I also had a long talk about a higher-level MPI API  
for Fortran.  I think this is a good thing to consider and I'm  
interesting in helping to write a reference implementation.  However,  
it is really outside of the scope of this committee.  Our current goal  
is to provide new Fortran bindings that resolve problems with the  
current Fortran bindings, but in doing so, don't stray too far off  
from the MPI spec.

However, regarding high-level Fortran interfaces, I'm planning on  
scheduling a teleconference with Douglas Gregor who in involved with  
the Boost MPI C++ library.  I announce more details when I get it set  
up.  If needs be we can take discussion of this high-level interface  
to another email group.

Cheers,
Craig