mpiexec and interactive read

[Troy Baer]

On Thu, 15 May 2003, Bryan Putnam wrote:
> I have a part of the famous "pi calculating" program below where node 0
> reads some input from the terminal. If I run this program using for
> example,
> 
> mpirun -np 4 -machinefile $PBS_NODEFILE prog
> 
> it runs normally, but when using
> 
> mpiexec -n 4 prog
> 
> the program doesn't appear to stop and wait at the read, and it complains
> about reading the end of file.
> 
> We're using Linux RedHat 7.3 and the problem occurs when compiling with
> both g77 and Portland pgf77. Any help appreciated!

By default, mpiexec only connects stdin to rank 0.  If you want it to
go to all MPI processes, do

mpiexec -allstdin prog

(mpiexec will figure out how many procs to use from the batch system,
so you don't need -n unless you want fewer MPI processes that CPUs
you requested for your job.)

	--Troy
-- 
Troy Baer                       email:  troy at osc.edu
Science & Technology Support    phone:  614-292-9701
Ohio Supercomputer Center       web:  http://oscinfo.osc.edu