使用 mpi4py 接收多个发送命令

如何修改以下代码（改编自http://materials.jeremybejarano.com/MPIwithPython/pointToPoint.html http://materials.jeremybejarano.com/MPIwithPython/pointToPoint.html）这样每个comm.Send实例接收者root = 0并打印输出。目前只收到第一个发送命令。

#passRandomDraw.py
import numpy
from mpi4py import MPI
from mpi4py.MPI import ANY_SOURCE
import numpy as np

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

if rank == 0:
    randNum = numpy.zeros(1)
    print "Process before receiving random numbers"


else:
    for i in range(0,np.random.randint(1,10),1):
        randNum = numpy.zeros(1)
        randNum = numpy.random.random_sample(1)
        print "Process", rank, "iteration", i, "drew the number", randNum[0]
        comm.Send(randNum, dest=0)


if rank == 0:
   comm.Recv(randNum, ANY_SOURCE)
   print "Process", rank, "received the number", randNum[0]

如果您不知道要发送多少条消息，那么您必须引入一条消息来标记消息结束。您可以通过使用特殊标签来通用地使用它。为了避免为终止消息提供不匹配的缓冲区，您可以使用probe检查传入的消息类型

tag_data = 42
tag_end = 23

if rank == 0:
    randNum = numpy.zeros(1)
    print "Process before receiving random numbers"
else:
    for i in range(0,np.random.randint(1,10),1):
        randNum = numpy.zeros(1)
        randNum = numpy.random.random_sample(1)
        print "Process", rank, "iteration", i, "drew the number", randNum[0]
        comm.Send(randNum, dest=0, tag=tag_data)
    # send the termination message. Using the lower-case interface is simpler
    comm.send(None, dest=0, tag=tag_end)

if rank == 0:
    # For debugging it might be better to use a list of still active procsses
    remaining = comm.Get_size() - 1
    while remaining > 0:
        s = MPI.Status()
        comm.Probe(status=s)
        # make sure we post the right kind of message
        if s.tag == tag_data:
            comm.Recv(randNum, s.source, tag=tag_data)
            print "Process ", s.source, " received the number", randNum[0]
        elif s.tag == tag_end:
            # don't need the result here
            print "Process ", rank, " is done"
            comm.recv(source=s.source, tag=tag_end)
            remaining -= 1

这有很多变体。例如，如果您知道某条消息是最后一条消息，则可以合并终止消息。