Thanks George, But what is the need for user to
specify it. The api can check the address of input buffers and output
buffers. Is there some extra advantage of MPI_IN_PLACE over automatically
detecting it using pointers?-NeerajOn Tue, 11 Dec 2007 06:10:06 -0500 Open MPI
Users wrote Neeraj, MPI_IN_PLACE is defined by the MPI standard in order
to allow the users to specify that the input and output buffers for the
collectives are the same. Moreover, not all collectives support MPI_IN_PLACE
and for those that support it some strict rules apply. Please read the
collective section in the MPI standard to see all the restrictions.
Thanks, george. On Dec 11, 2007, at 5:56 AM, Neeraj Chourasia wrote:
> Hello everyone, > > While going through collective
algorithms, I came across > preprocessor directive MPI_IN_PLACE which is
(void *)1. Its always > being compared against source buffer(sbuf). My
question is when > MPI_IN_PLACE == sbuf condition would be true. As far
as i > understand, sbuf is the address of source buffer, which every node
> has to transfer to remaining nodes based on recursive doubling or
> say bruck algo. And it can never be equal to (void *)1. Any help is
> appreciated. > > Regards > Neeraj > >
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