# Six calls to sends and receives have been removed from the
# code below, and you must add back the appropriate sends and
# receives with the appropriate arguments at sites marked by:
#
# # MISSING IPC CALL
#
# At each site, a call to an MPI send or receive function is
# needed with two aruments, the first being the message a
ay
# object that is being sent or received and the second being
# a specification of the communicating partner:
#
# comm.Send( ____, dest=____ )
#
# o
#
# comm.Recv( ____, source=____ )
#
# Note that the server must be able to receive from any client.
# This is an example of the "select" functionality described in
# section XXXXXXXXXXThe ability for a server to select a message
# from any client is easy to code with MPI in Python. See
# https:
nyu-cds.github.io/python-mpi/02-messagepassing/ fo
# a tutorial on MPI blocking sends and receives in Python.
#
# Example command line to run this program:
#
# mpiexec -n 3 python mpi3.py
#
# (the number of processes given by -n should be 2 or more)
#
# The server process has rank 0. It maintains a sum variable,
# which it updates based on requests from clients. The serve
# will also receive completion messages from clients and will
# terminate when all the clients have completed.
#
# The client processes have ranks 1 and above, which are used as
# the client numbers. A client process sends an update request
# and then waits on an acknowledgement reply from the server.
# After a given number of update requests, each client sends a
# completion message to the server and then waits on an
# acknowledgement reply from the server.
#
# The update message format from a client to the server is:
#
# [
]
#
# (where value == 0 is used as a sentinel value for completion)
#
# All requests are acknowledged by the server in a reply message.
# The reply message format from the server is:
#
# [ 0 1 ]
#
# Note that all messages start with the rank of the process that
# is sending the message. This message protocol allows the
# server process to know the identity of the requesting client
# when a request is selected by the server's call to the MPI
# receive function.
#
# numpy is used for more efficient numeric a
ays.
import numpy
from mpi4py import MPI
comm = MPI.COMM_WORLD
ank = comm.Get_rank()
num_clients = comm.Get_size() - 1
if num_clients <= 0:
print 'command line argument does not allow clients'
raise SystemExit
# client code
if rank != 0:
request = numpy.zeros( 2, dtype='i' )
reply = numpy.zeros( 2, dtype='i' )
for i in range( 1, 3 ):
request[0] = rank
request[1] = i * rank
# MISSING IPC CALL # for update request
# MISSING IPC CALL # for reply
print 'client', rank, 'received acknowledgement'
request[0] = rank
request[1] = 0
# MISSING IPC CALL # for completion notice
# MISSING IPC CALL # for reply
print 'client', rank, 'done'
# server code
else:
print 'simple server with', num_clients, 'clients'
sum = 0
print 'server starts with a sum value of', sum
service_request = numpy.zeros( 2, dtype='i' )
acknowledgement = numpy.zeros( 2, dtype='i' )
acknowledgement[0] = 0
acknowledgement[1] = 1
while num_clients > 0:
# MISSING IPC CALL
if service_request[1] != 0:
print 'server received update from client',
print service_request[0]
sum += service_request[1]
print 'server added', service_request[1],
print 'and sum is now', sum
else:
print 'server receives completion notice',
print 'from client', service_request[0]
num_clients -= 1
# MISSING IPC CALL
print 'server done'