Python Mpi Sendrecv() To Pass A Python Object

I am trying to use mpi4py's sendrecv() to pass a dictionary obj. from mpi4py import MPI comm=MPI_COMM_WORLD rnk=comm.Get_rank() size=comm.Get_size() idxdict={1:2} buffer=None com

Solution 1:

I believe the documentation is misleading here; sendrecv returns the received buffer, and doesn't use the receive object argument at all that I can see (at least in older versions, 1.2.x). So your above code doesn't work (although the receive does in fact happen), but the below does:

from mpi4py import MPI
comm=MPI.COMM_WORLD
rnk=comm.Get_rank()
size=comm.Get_size()

idxdict={1:2}
buffer = comm.sendrecv(sendobj=idxdict,dest=(rnk+1)%size,source=(rnk-1+size)%size)

print "idxdict = ", idxdict
print "buffer = ", buffer