并行Python - 如何使用输出数据？

Question

嘿，我是Parallel Python的新手，正在写一段简单的代码来并行加数字。代码可以正常工作，能把数字加起来，但我想知道在任务完成后，怎么使用这些输出结果？我的代码如下：

import sys, time
import pp
import numpy
x = numpy.arange(-20.0,20.0,0.5)
grav = []
gravity = numpy.zeros([4,1])
def function(raw_input,x,grav):
    f = 0
    for i in numpy.arange(len(x)):
        f+=1
    a=raw_input[0]
    b=raw_input[1]
    c=raw_input[2]
    d=raw_input[3]
    grav.append((a+b+c+d)+f)
    return grav
for i in numpy.arange(2):
    # tuple of all parallel python servers to connect with
    ppservers = ()
    #ppservers = ("10.0.0.1",)

    if len(sys.argv) > 1:
        ncpus = int(sys.argv[1])
        # Creates jobserver with ncpus workers
        job_server = pp.Server(ncpus, ppservers=ppservers)
    else:
        # Creates jobserver with automatically detected number of workers
        job_server = pp.Server(ppservers=ppservers)

    print "Starting pp with", job_server.get_ncpus(), "workers"
    start_time = time.time()

    # The following submits 4 jobs and then retrieves the results
    puts = ([1,2,3,4], [3,2,3,4],[4,2,3,6],[2,3,4,5])

    jobs = [(raw_input, job_server.submit(function,(raw_input,x,grav), (), ("numpy",))) for raw_input in puts]
    for raw_input, job in jobs:
        print "Sum of numbers", raw_input, "is", job()
    print grav
    print "Time elapsed: ", time.time() - start_time, "s"
    job_server.print_stats()
    print gravity
    #gravity[i] = grav

这段代码会打印出4个结果，分别是90、92、95和94，还会给出一些统计信息。我的问题是，我该如何使用这4个结果数字呢？我想把它们放到一个叫做gravity的数组里，但我不知道怎么做。谢谢！

Answer 1

你需要把 job() 函数的结果保存起来。可以试试下面的代码：

import sys, time
import pp
import numpy
x = numpy.arange(-20.0,20.0,0.5)
grav = []
gravity = numpy.zeros([4,1])
def function(raw_input,x,grav):
    f = 0
    for i in numpy.arange(len(x)):
        f+=1
    a=raw_input[0]
    b=raw_input[1]
    c=raw_input[2]
    d=raw_input[3]
    grav.append((a+b+c+d)+f)
    return grav

jobsList = []

for i in numpy.arange(2):
    # tuple of all parallel python servers to connect with
    ppservers = ()
    #ppservers = ("10.0.0.1",)

    if len(sys.argv) > 1:
        ncpus = int(sys.argv[1])
        # Creates jobserver with ncpus workers
        job_server = pp.Server(ncpus, ppservers=ppservers)
    else:
        # Creates jobserver with automatically detected number of workers
        job_server = pp.Server(ppservers=ppservers)

    print "Starting pp with", job_server.get_ncpus(), "workers"
    start_time = time.time()

    # The following submits 4 jobs and then retrieves the results
    puts = ([1,2,3,4], [3,2,3,4],[4,2,3,6],[2,3,4,5])

    jobs = [(raw_input, job_server.submit(function,(raw_input,x,grav), (), ("numpy",))) for raw_input in puts]
    for raw_input, job in jobs:
        r = job()
        jobsList.append(r)
        print "Sum of numbers", raw_input, "is", r
    print grav
    print "Time elapsed: ", time.time() - start_time, "s"
    job_server.print_stats()
    print gravity
    for job in jobsList:
        print job