How to Run MPI Programs Interactively

MPICH mpirun command starts up MPI programs

where do the processes run:

• SMP computer - any processors that are available
• distributed computer - nodes in file /MPICH_DIR/share/machines.ARCH (for example: machines.LINUX)
• distributed computer - runs one process on node where mpirun comand was executed

Use mpirun -help to see command line options

On andes SMP computer:

andes:~> mpirun -np 4 hello_world_c
Hello world from process 1 of 4
Hello world from process 2 of 4
Hello world from process 3 of 4
Hello world from process 0 of 4

  
On Discovery cluster interactive nodes t01,t02,t03:

[sas@t01]$ mpirun -np 4  hello_world_c
Hello world from process 0 of 4
Hello world from process 1 of 4
Hello world from process 3 of 4
Hello world from process 2 of 4

[sas@t01]$ mpirun -np 4 -t hello_world_c
Procgroup file:
t01.bw01.dartmouth.edu 0 /home/sas/Classes/intro_mpi/hello_world_c
t01 1 /home/sas/Classes/intro_mpi/hello_world_c
t01 1 /home/sas/Classes/intro_mpi/hello_world_c
t01 1 /home/sas/Classes/intro_mpi/hello_world_c
/home/sas/Classes/intro_mpi/hello_world_c -p4pg /home/sas/Classes/intro_mpi/PI11653 \
 -p4wd /home/sas/Classes/intro_mpi

[sas@t01]$ cat machine.file
t01
t01
t01
t01
t02
t02
t02
t02

[sas@t01]$ mpirun -np 8 -t -machinefile machine.file hello_world_c 
Procgroup file:
t01.bw01.dartmouth.edu 0 /home/sas/Classes/intro_mpi/hello_world_c
t01 1 /home/sas/Classes/intro_mpi/hello_world_c
t01 1 /home/sas/Classes/intro_mpi/hello_world_c
t01 1 /home/sas/Classes/intro_mpi/hello_world_c
t02 1 /home/sas/Classes/intro_mpi/hello_world_c
t02 1 /home/sas/Classes/intro_mpi/hello_world_c
t02 1 /home/sas/Classes/intro_mpi/hello_world_c
t02 1 /home/sas/Classes/intro_mpi/hello_world_c