Question

I have two different functions f, and g that compute the same result with different algorithms. Sometimes one or the other takes a long time while the other terminates quickly. I want to create a new function that runs each simultaneously and then returns the result from the first that finishes.

I want to create that function with a higher order function

h = firstresult(f, g)

What is the best way to accomplish this in Python?

I suspect that the solution involves threading. I’d like to avoid discussion of the GIL.

Answer 1

Now – unlike my suggestion on the other answer, this piece of code does exactly what you are requesting:

from multiprocessing import Process, Queue

import random
import time


def firstresult(func1, func2):
    queue = Queue()
    proc1 = Process(target=func1,args=(queue,))
    proc2 = Process(target=func2, args=(queue,))
    proc1.start();proc2.start()
    result = queue.get()
    proc1.terminate(); proc2.terminate()
    return result

def algo1(queue):
    time.sleep(random.uniform(0,1))
    queue.put("algo 1")

def algo2(queue):
    time.sleep(random.uniform(0,1))
    queue.put("algo 2")

print firstresult(algo1, algo2)