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The MPICH test suite, in examples/test, performs a fairly complete test
of an MPI implementation. If there is an error, it usually indicates a
problem with the implementation of MPI; if you encounter such a problem,
please report it to mpi-bugs@mcs.anl.gov.
However, there are a few exceptions that are described here.



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1. Q:
The test pt2pt/structf fails with
0 - Error in MPI_ADDRESS : Invalid argument: Address of location
given to MPI_ADDRESS does not fit in Fortran integer
[0] Aborting program!
A:
This is not an error; it is a gap in the MPI-1 definition, fixed in
MPI-2. This indicates that Fortran integers are not large enough to hold an
address. This does indicate that MPI programs written in Fortran should not
use the MPI_Address function on this system.
2. Q:
The test env/timers fails with
Timer around sleep(1) did not give 1 second; gave 0.399949
A:
The low-level software that MPICH uses probably makes use of the
SIGALRM signal, thus denying it to the user's program. This is not an
error (the standard permits systems to make use of any signals) though it is
unfortunate.
One system known to use SIGALRM is the IBM MPL/POE (device
ch_mpl) software for using the High Performance Switch
in the IBM SP parallel computers.



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