Rainer,
Thank you for taking time to reply to my querry. Do I understand correctly that external32 data representation for i/o is not implemented? I am puzzled since the MPI-2 standard clearly indicates the existence of external32 and has lots of words regarding how nice this feature is for file interoperability. So do both Open MPI and MPIch2 not adhere to the standard in this regard? If this is really the case, how difficult is it to define a custom data representation that is 32-bit big endian on all platforms? Do you know of any documentation that explains how to do this?
  Thanks again.

   ---Tom

Rainer Keller wrote:
Hello Tom,
like MPIch2, Open MPI also uses ROMIO as underlying MPI-IO implementation as an mca. ROMIO implements the native datarep.

With best regards,
Rainer


On Friday 05 January 2007 20:38, l...@cora.nwra.com wrote:
Hi,
   I am attempting to use the 'external32' data representation in order
read and write portable data files.  I believe I understand how to do
this, but I receive the following run-time error from the
mpi_file_set_view call:

MPI_FILE_SET_VIEW (line 118): **unsupporteddatarep

If I replace 'external32' with 'native' in the mpi_file_set_view call then
everything works, but the data file is written in little endian order on
my Opteron cluster.  Just for grins I also tried 'internal' but this
produces the unsupporteddatarep error as well.

Is the 'external32' data type implemented?  Do I need to do something else
to access it?  I looked in the FAQs as well as the mailing list archives
but I can not seem to find any threads discussing this issue.  I would
greatly appreciate any advice.

I have attached my sample fortran codes (explicit_write.f,
explicit_read.f, Makefkile) as well as the config.log, output of
ompi_info, and my environment variable settings.  I am running Fedora Core
4 with the 2.6.17-1.2142_FC4smp kernel.

Thanks,

   ---Tom



--
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  Thomas S. Lund
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