Dear all,
I'm just trying some very basic stuff with MPI_COMM_SPAWN in
python (i.e. I use mpi4py package), but I see behaviour that I
do not understand - the child process gets spawned, does its
stuff and then "should" finish. I see though, that the process
created for the child stays alive. I see this only with the
MPICH, OPENMPI does what I would (naively) expect. In this way I
can end up with N "ghost" process, after calling SPAWN N-times.
My minimal working example is following:
______________________________________________
parent.py
from __future__ import print_function
from mpi4py import MPI
comm = MPI.COMM_WORLD
spawned =
MPI.COMM_SELF.Spawn(sys.executable,args=['child.py'],maxprocs=1)
print("parent process is waiting for child")
spawned.Barrier()
______________________________________________
child.py
from __future__ import print_function
from mpi4py import MPI
parent = MPI.Comm.Get_parent()
# just do some stupid stuff that takes a bit of time
for i in range(5000000):
a = i*i+1-(i*10) + math.sin(math.pow(i,i%8))
parent.Barrier()
______________________________________________
I run with e.g.:
mpirun -n 1 python mpi.py
Do I miss something with SPAWN method?
(I tested on two independent systems, our local cluster with
mpich v3.0.4, and my laptop - fedora 26, mpich v3.2.8 from
repositories)
thank you very much for suggestions.
Regards,
stanislav.
_______________________________________________
discuss mailing list discuss@mpich.org
To manage subscription options or unsubscribe:
https://lists.mpich.org/mailman/listinfo/discuss