[Mpi3-ft] The state of MPI is undefined

Josh Hursey jjhursey at open-mpi.org
Wed Jun 8 13:35:56 CDT 2011

Per our conversation today, we wanted to have a paragraph clearly
defining what the MPI standard means by 'After an error is detected,
the state of MPI is undefined.'. Since it is defined for some classes
of errors. The paragraph would clarify further references of this
nature in the MPI standard.

Note that this is slightly different than when the program (code) is
erroneous due to misuse of the MPI standard interfaces.

A few places in the text to look:
 - Section 2.8: Error Handling - Paragraph 1 and 6
 - Section 8.3: Error Handling - Paragraphs 6 and 7.
 - Section 13.7: I/O Error Handling - Advice to users

If the MPI implementation returns an error of MPI_ERR_RANK_FAIL_STOP
then it must provide the semantics defined in Chapter 17. We are not,
at this time, defining the semantic behavior of the MPI standard after
returning other errors.

Any suggestions on possible wording?
Something like "The state of the computation after an error has
occurred may be undefined. A high-quality implementation will continue
afterwards. IF the implementation returns an error and the semantics
after the error are defined in the standard (e.g.,
MPI_ERR_RANK_FAIL_STOP in Chapter 17), then the implementation must
provide the specified semantics."

Any suggestions on where to put the wording?
It was suggested that we change/update paragraphs 6 and 7 in Section
8.3 appropriately.


Joshua Hursey
Postdoctoral Research Associate
Oak Ridge National Laboratory

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