多处理一个for循环与多个参数，这取决于循环索引

Question

你好我想多处理一个for循环，我计算4个不同的独立函数。唯一的问题是这些函数需要多个参数。其中一些参数是使用循环索引选择正确元素的列表。这里是一个示例代码

import numpy as np 

def function_1(a,b,c,d): 
    #do heavy calculations 
    #function is written in fortran and linked via f2py 
def function_2(a,b,c,d): 
    #do heavy calculations 
    #function is written in fortran and linked via f2py 
def function_3(a,b,c,d): 
    #do heavy calculations 
    #function is written in fortran and linked via f2py 
def function_4(a,b,c,d): 
    #do heavy calculations 
    #function is written in fortran and linked via f2py 
result_1 = 0 
result_2 = 0 
result_3 = 0 
result_4 = 0 
a = [1,2,3] 
b = [4,5,6] 
c = 2 
d = 5 
for k in xrange(3): 
    result_1 += function_1(a[k],b[k],k*c,d) 
    result_2 += function_2(a[k],b[k],k*c,d) 
    result_3 += function_3(a[k],b[k],k*c,d) 
    result_4 += function_4(a[k],b[k],k*c,d) 

有没有办法做到这些计算并行而不是顺序？ 对于在fortran中编写的函数，可以这样做吗？

Answer 1

def gen_func(idx, *args): 
    def function_1(*args): 
    i_want_2 = args[:2] 
    return sum(i_want_2) 
    def function_2(*args): 
    i_want_3 = args[:3] 
    return sum(i_want_3) 
    def function_3(*args): 
    return sum(args) 
    def function_4(*args): 
    return sum(args) 

    result = 0 
    func = {0:function_1,1:function_2,2:function_3,3:function_4} 
    for a_k, b_k in zip(args[0], args[1]): 
    result += func[idx](a_k, b_k,*args[2:]) 

    print idx, result 




import multiprocessing 
    jobs = [] 
    a = [1,2,3] 
    b = [4,5,6] 
    c = 2 
    d = 5 
    for i in range(4): 
    p = multiprocessing.Process(target=gen_func, args=(i,a,b,c,d,)) 
    jobs.append(p) 
    p.start() 

输出：

0 21 
1 27 
2 42 
3 42 

Answer 2

，如果它不容易做这样的事情，我只是在想：

import numpy as np 

def function_1(a,b,c,d): 
    #do heavy calculations 
    #function is written in fortran and linked via f2py 
def function_2(a,b,c,d): 
    #do heavy calculations 
    #function is written in fortran and linked via f2py 
def function_3(a,b,c,d): 
    #do heavy calculations 
    #function is written in fortran and linked via f2py 
def function_4(a,b,c,d): 
    #do heavy calculations 
    #function is written in fortran and linked via f2py 
result_1 = 0 
result_2 = 0 
result_3 = 0 
result_4 = 0 
a = [1,2,3] 
b = [4,5,6] 
c = 2 
d = 5 
for k in xrange(3): 
    p_1 = multiprocessing.Process(target = function_1, (a[k],b[k],k*c,d)) 
    p_1.start() 
    p_2 = multiprocessing.Process(target = function_2, (a[k],b[k],k*c,d)) 
    p_2.start() 
    p_3 = multiprocessing.Process(target = function_3, (a[k],b[k],k*c,d)) 
    p_3.start() 
    p_4 = multiprocessing.Process(target = function_4, (a[k],b[k],k*c,d)) 
    p_4.start() 
    #wait till process finishes is there such an option? 
    result_1 += p_1 
    result_2 += p_2 
    result_3 += p_3 
    result_4 += p_4 
    #does the process return a complex number?