[mpich-discuss] MPI_Comm_size

[Rajeev Thakur]

It often means that the mpif.h that got picked up in the compile step is
from a different MPI implementation. Make sure there is no mpif.h file
in the subdirectories containing your application, and use the
mpif77/mpif90 script provided by the MPI implementation to compile your
program.
 
Rajeev
 


  _____  

From: mpich-discuss-bounces at mcs.anl.gov
[mailto:mpich-discuss-bounces at mcs.anl.gov] On Behalf Of xiao zhang
Sent: Monday, July 06, 2009 1:55 PM
To: mpich-discuss at mcs.anl.gov
Subject: [mpich-discuss] MPI_Comm_size


HI~ Everyone: i have a little doubt about the funtion:
MPI_Comm_size
If I call it like:

include 'mpif.h'
integer :: ierr
call MPI_Init(ierr)
call MPI_Comm_size(MPI_COMM_WORLD,mgroupsize,ierr)

Then I use 8 processors to run the program, the return value of
mgroupsize should be 8. Is that right?
If it is right, the return value for me is just 1.   What would be the
possible problem?
 
 I am really new to this and thank you very much
                                   Xia


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