Two functions in parallel with multiple arguments and return values

Question

I\'ve got two separate functions. Each of them takes quite a long time to execute.

def function1(arg):
     do_some_stuff_here
     return result1

def function2         


        

Answer 1

Here is an example of:

1. Run a single function with multiple inputs in parallel using a Pool (square function) Interesting Side Note the mangled op on lines for "5 981 25"
2. Run multiple functions with different inputs (Both args and kwargs) and collect their results using a Pool (pf1, pf2, pf3 functions)

import datetime
import multiprocessing
import time
import random

from multiprocessing import Pool

def square(x):
    # calculate the square of the value of x
    print(x, x*x)
    return x*x

def pf1(*args, **kwargs):
    sleep_time = random.randint(3, 6)
    print("Process : %s\tFunction : %s\tArgs: %s\tsleeping for %d\tTime : %s\n" % (multiprocessing.current_process().name, "pf1", args, sleep_time, datetime.datetime.now()))
    print("Keyword Args from pf1: %s" % kwargs)
    time.sleep(sleep_time)
    print(multiprocessing.current_process().name, "\tpf1 done at %s\n" % datetime.datetime.now())
    return (sum(*args), kwargs)

def pf2(*args):
    sleep_time = random.randint(7, 10)
    print("Process : %s\tFunction : %s\tArgs: %s\tsleeping for %d\tTime : %s\n" % (multiprocessing.current_process().name, "pf2", args, sleep_time, datetime.datetime.now()))
    time.sleep(sleep_time)
    print(multiprocessing.current_process().name, "\tpf2 done at %s\n" % datetime.datetime.now())
    return sum(*args)

def pf3(*args):
    sleep_time = random.randint(0, 3)
    print("Process : %s\tFunction : %s\tArgs: %s\tsleeping for %d\tTime : %s\n" % (multiprocessing.current_process().name, "pf3", args, sleep_time, datetime.datetime.now()))
    time.sleep(sleep_time)
    print(multiprocessing.current_process().name, "\tpf3 done at %s\n" % datetime.datetime.now())
    return sum(*args)

def smap(f, *arg):
    if len(arg) == 2:
        args, kwargs = arg
        return f(list(args), **kwargs)
    elif len(arg) == 1:
        args = arg
        return f(*args)


if __name__ == '__main__':

    # Define the dataset
    dataset = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]

    # Output the dataset
    print ('Dataset: ' + str(dataset))

    # Run this with a pool of 5 agents having a chunksize of 3 until finished
    agents = 5
    chunksize = 3
    with Pool(processes=agents) as pool:
        result = pool.map(square, dataset)
    print("Result of Squares : %s\n\n" % result)
    with Pool(processes=3) as pool:
        result = pool.starmap(smap, [(pf1, [1,2,3], {'a':123, 'b':456}), (pf2, [11,22,33]), (pf3, [111,222,333])])

    # Output the result
    print ('Result: %s ' % result)


Output:
*******

Dataset: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
1 1
2 4
3 9
4 16
6 36
7 49
8 64
59 81
 25
10 100
11 121
12 144
13 169
14 196
Result of Squares : [1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196]


Process : ForkPoolWorker-6  Function : pf1  Args: ([1, 2, 3],)  sleeping for 3  Time : 2020-07-20 00:51:56.477299

Keyword Args from pf1: {'a': 123, 'b': 456}
Process : ForkPoolWorker-7  Function : pf2  Args: ([11, 22, 33],)   sleeping for 8  Time : 2020-07-20 00:51:56.477371

Process : ForkPoolWorker-8  Function : pf3  Args: ([111, 222, 333],)    sleeping for 1  Time : 2020-07-20 00:51:56.477918

ForkPoolWorker-8    pf3 done at 2020-07-20 00:51:57.478808

ForkPoolWorker-6    pf1 done at 2020-07-20 00:51:59.478877

ForkPoolWorker-7    pf2 done at 2020-07-20 00:52:04.478016

Result: [(6, {'a': 123, 'b': 456}), 66, 666] 

Process finished with exit code 0