[petsc-users] How to understand these error messages

Jed Brown jedbrown at mcs.anl.gov
Wed Oct 23 17:22:29 CDT 2013

Fande Kong <fd.kong at siat.ac.cn> writes:

> Hi Barry,
> I contacted the supercomputer center, and they asked me for a test case so
> that they can forward it to IBM. Is it possible that we write a test case
> only using MPI?  It is not a good idea that we send them the whole petsc
> code and my code.

This may be possible, but this smells of a message ordering/rendezvous
problem, in which case you'll have to reproduce essentially the same
communication pattern.  The fact that you don't see the error sooner in
your program execution (and that it doesn't affect lots of other people)
indicates that the bug may be very specific to your communication
pattern.  In fact, it is likely that changing your element distribution
algorithm, or some similar changes, may make the bug vanish.
Reproducing all this matching context in a stand-alone code is likely to
be quite a lot of effort.

I would configure the system to dump core on errors and package up the
test case.
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