Re: MPI_FINALIZE

[William Gropp <gropp@mcs.anl.gov>]

At 10:54 AM 5/10/2001 -0400, Nicholas Nevin - Sun HPC High Performance 
Computing wrote:

>Correct handling of my most disliked feature in MPI, the cancelling of
>sends, seems to require a barrier or something similar in
>MPI_Finalize.
>
>See example 3.4 in section 3.2.2 (Clarification of MPI_Finalize) of the MPI-2
>standard. Pages 23-24.

I read that text as saying the opposite; see in particular examples 3.1 and 
3.2 (replacing MPI_Request_free with MPI_Cancel).  Example 3.4 says only 
that MPI_Finalize may need to wait if there are incomplete messages that 
could be but have not yet been cancelled.  This example only says that it 
is erroneous for an implementation to complain about unreceived messages at 
MPI_Finalize unless it can guarantee that that unreceived message won't be 
cancelled by the sending process.  The "advice to implementors" suggests a 
sufficient but not necessary solution (use a barrier).

Bill