multiprocessing example

multiprocessing_example.py

import multiprocessing
import numpy as np
import time

def compute_something(input):
    a = input[0]
    b = input[1]
    r = a**b**b
    return r


if __name__ == '__main__':

    inputs = [[np.random.randint(1,10), np.random.randint(1,7)] for i in range(1000)]

    # not parallel:
    t_start = time.time()
    r = [compute_something(inp) for inp in inputs]
    print('Not parallel: ' + str(time.time() - t_start) + ' sec')

    # parallel:
    ncores = int(0.9*multiprocessing.cpu_count())
    t_start = time.time()
    pool = multiprocessing.Pool(ncores)
    r = pool.map(compute_something, inputs)
    print('Parallel: ' + str(time.time() - t_start) + ' sec, with ' + str(ncores) + ' cpu cores')