Whatever "icky" means, it is possible to write correct calls to MPI_COMM_SPAWN and MPI_COMM_SPAWN_MULTIPLE and to correctly catch the arguments by the MPI library routine. Therefore, I would not spend additional work into this interface. My opinion: it is not worth to spend to much effort in MPI Spawn. Rolf ----- Original Message -----

From: "Craig Rasmussen" <[email protected]> To: "MPI-3 Fortran working group" <[email protected]> Sent: Wednesday, May 26, 2010 3:52:46 PM Subject: Re: [MPI3 Fortran] MPI-2 Fortran question: 2D char array in MPI_COMM_SPAWN_MULTIPLE

Just to clarify.  Jeff and I believe the spec is "icky" (Jeff's words not mine :-)  ).  There may be ways to fix make it better in MPI-3.  I'll think about it and send out an email later to see if anyone has ideas on how to improve it.

-craig

On Tue, May 25, 2010 at 2:41 PM, Jeff Squyres < [email protected] > wrote:

On May 25, 2010, at 4:23 PM, Rolf Rabenseifner wrote:

...

MPI-2.2, p310:18-25 defines:

"The argv argument argv is an array of strings containing arguments that are passed to the program. The first element of argv is the first argument passed to command, not, as is conventional in some contexts, the command itself. The argument list is terminated by NULL in C and C++ and an empty string in Fortran.

I mis-read this last line when I read it -- now I understand what Rolf is saying (and, in fact, it's exactly what someone said earlier that the spec would need to be right).

Thanks Rolf!

...

The code fragment below is wrong because it does try to detect an overall second_dim_size instead of individual second_dim_size(i) for i=1,count.

Also a good point -- in OMPI, we assume that all the argv arrays will have the same number of tokens for each command.  But this is not necessarily the case.  I'll fix.

Thanks!

-- Jeff Squyres [email protected] For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/

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-- Dr. Rolf Rabenseifner . . . . . . . . . .. email [email protected] High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530 University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832 Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner Nobelstr. 19, D-70550 Stuttgart, Germany . (Office: Allmandring 30)