Exporting plots in parallel using concurrent.futures

parallel_plot.py

import concurrent.futures
import matplotlib.pyplot as plt
import numpy as np
import time, random

def do_stuff(a):   # these are examples.
    x = np.linspace(1,10)
    plt.plot(x, np.cos(a*x))
    plt.savefig('{}.png'.format(a))
    time.sleep(random.random())
    print(a)
    return a

output = list()
alist = [1,2,3,4,5,6,7,8,9]  # a = 1, 2, 3

with concurrent.futures.ProcessPoolExecutor() as executor:
    for out in executor.map(do_stuff, alist):
        output.append(out)

print(output)  # map maps correct output independent of process order