在Python中并行化四个嵌套循环

Question

我有一个相当简单的嵌套for循环,迭代四个数组:

for a in a_grid:
    for b in b_grid:
        for c in c_grid:
            for d in d_grid:
                do_some_stuff(a,b,c,d)  # perform calculations and write to file

也许这不是开始在4D网格上执行计算的最有效方法.我知道joblib能够像这样并行化两个嵌套的for循环,但是我很难将它概括为四个嵌套循环.有任何想法吗？

Answer 1

我通常使用这种形式的代码:

#!/usr/bin/env python3
import itertools
import multiprocessing

#Generate values for each parameter
a = range(10)
b = range(10)
c = range(10)
d = range(10)

#Generate a list of tuples where each tuple is a combination of parameters.
#The list will contain all possible combinations of parameters.
paramlist = list(itertools.product(a,b,c,d))

#A function which will process a tuple of parameters
def func(params):
  a = params[0]
  b = params[1]
  c = params[2]
  d = params[3]
  return a*b*c*d

#Generate processes equal to the number of cores
pool = multiprocessing.Pool()

#Distribute the parameter sets evenly across the cores
res  = pool.map(func,paramlist)