if I understand your proposal right,
then you say, that we should allow only
- portable datatypes, and
- datatype, received with MPI_TYPE_RECV from the
as target_datatype in MPI_PUT and MPI_GET.
I believe, that we can ommit 2 pages in the draft, if we say
- with MPI_PUT and MPI_GET he/she should only use portable
- and if he/she wants to use nonportable datatypes, then
he/she is responsible to use the right displacements
(i.e. on th origin host he/she must use displacements
that are valid on the target system)
- MPI-2 does not support the transfer of datatypes itself,
- MPI-2 votes for MPI_TYPE_SIMPLE_STRUCT along with the
votes for one-sided communication.
I think if we define MPI_TYPE_SIMPLE_STRUCT, then there is
no real reason for nonportable datatypes!
And therefore no real reason for MPI_TYPE_SEND and _RECV!
But if the MPI-2 forum believes that we should support
MPI_TYPE_SEND and _RECV then your ideas are good.
Rolf Rabenseifner (Computer Center )
Rechenzentrum Universitaet Stuttgart (University of Stuttgart)
Allmandring 30 Phone: ++49 711 6855530
D-70550 Stuttgart 80 FAX: ++49 711 6787626