Re: [mpi-21] F90 bindings

[Purushotham Bangalore <puri@xxxxxxxxxxx>]

Jeff raises an important issue here. In it's current form are the F90 bindings really useful? Should we just move on to the next version of Fortran (2003 or 2008) and deprecate the F90 bindings? Anyone received any feedback on this issue from F90 users?

Puri
----- Original Message -----
From: "Jeff Squyres" <jsquyres@xxxxxxxxx>
To: mpi-21@xxxxxxxxxxxxx
Sent: Friday, December 7, 2007 7:23:57 AM (GMT-0600) America/Chicago
Subject: [mpi-21] F90 bindings

The F90 bindings specified in MPI-2 currently require nearly 7 million  
interface functions in the Fortran 90 module (!).  This large number  
of interfaces is required because F90 is a strongly-typed language and  
has no analogue of (void*).  MPI_SEND, for example, has to be  
overloaded with function signatures for every possible type of choice  
buffer.  Worse, many collectives have *2* choice buffers... the end  
result is that nearly 7M interfaces are needed.  As result, many MPI  
implementations implement only a fraction of the MPI F90 module  
interface functions.

Additionally, user-defined F90 types cannot be supported.

This is clearly a [big] bug in the F90 bindings.  What does the Forum  
want to do about this for MPI-2.1?  Perhaps add some clarification  
language?  Or ...?

Can this issue be added to the discussion list for the bindings  
subcommittee?

-- 
Jeff Squyres
Cisco Systems