[MPICH] MPI_Finalize preconditions

[Angel Tsankov]

OK, I think I need to clarify my question, too. So, let's assume that 
the process has received all incoming messages. It, however, has 
initiated at least one send operation via a call to MPI_Isend or 
MPI_Send_init. However, the process has not explicitly completed any 
of these send operations. Assuming that the program is written 
correctly, i.e. those send operations have matching receive operations 
(possibly in other processes), is it safe to call MPI_Finalize right 
after a call to MPI_Barrier( MPI_COMM_WORLD ) has returned?

I guess it is also a good idea, if Rob explains what he means by "all 
sends have completed".

> Actually I should clarify that.  If the process has received all 
> incoming messages *and* all sends have completed, then the process 
> is ready to call finalize.
>
> Rob
>
> Rob Ross wrote:
>> Hi Angel,
>>
>> If a given process has received all incoming messages, then that 
>> process is ready to call finalize.  You don't have to perform the 
>> barrier operation; it's just extra overhead.
>>
>> Regards,
>>
>> Rob
>>
>> Angel Tsankov wrote:
>>> The MPI standard says:
>>> "The user must ensure that all pending communications involving a 
>>> process completes before the process calls MPI_FINALIZE."
>>>
>>> If each nonblocking receive call has a matching wait call, does a 
>>> call to MPI_Barrier( MPI_COMM_WORLD ) in all processes (and after 
>>> the wait calls) ensure that all communications involving the 
>>> processes have completed?
>>
>
>