#!/usr/bin/env python

if False:
    import mpi4py

    name = "name"  # lib{name}.so
    path = []
    mpi4py.profile(name, path=path)

from mpi4py import MPI

comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()

src = rank - 1
dest = rank + 1
if rank == 0:
    src = size - 1
if rank == size - 1:
    dest = 0

try:
    from numpy import zeros

    a1 = zeros(1000000, "d")
    a2 = zeros(1000000, "d")
except ImportError:
    from array import array

    a1 = array("d", [0] * 1000)
    a1 *= 1000
    a2 = array("d", [0] * 1000)
    a2 *= 1000

comm.Sendrecv(
    sendbuf=a1,
    recvbuf=a2,
    source=src,
    dest=dest,
)

MPI.Request.Waitall([
    comm.Isend(a1, dest=dest),
    comm.Irecv(a2, source=src),
])