Source code for pypdevs.middleware

# Copyright 2014 Modelling, Simulation and Design Lab (MSDL) at 
# McGill University and the University of Antwerp (http://msdl.cs.mcgill.ca/)
# 
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""
Middleware detection and setup code
"""

import sys

[docs]def startupMiddleware(): """ Do the actual detection and startup, also defines all necessary globals :returns: tuple -- current server rank and total world size """ if "MPI" in globals(): # Force local simulation return 0, 1 # Try loading MPI global COMM_WORLD global MPI try: from mpi4py import MPI COMM_WORLD = MPI.COMM_WORLD except ImportError: # No MPI4Py found, so force local MPI simulation from pypdevs.MPIRedirect import MPIFaker COMM_WORLD = MPIFaker() # Now we should take care of the starting of the server rank = COMM_WORLD.Get_rank() if rank != 0: # We should stop immediately, to prevent multiple constructions of the model # This is a 'good' stop, so return with a zero from pypdevs.server import Server server = Server(int(rank), COMM_WORLD.Get_size()) sys.exit(0) else: # We should still shutdown every simulation kernel at exit by having the controller send these messages # Use the atexit code at the end if COMM_WORLD.Get_size() > 1: import atexit atexit.register(cleanupMPI) return 0, COMM_WORLD.Get_size()
[docs]def cleanupMPI(): """ Shut down the MPI backend by sending a termination message to all listening nodes """ for i in range(COMM_WORLD.Get_size()): if i == COMM_WORLD.Get_rank(): req = COMM_WORLD.isend(0, dest=i, tag=0) else: COMM_WORLD.send(0, dest=i, tag=0) if COMM_WORLD.Get_size() > 1: MPI.Request.wait(req)