[PYTHON] Asynchronously run matplotlib interactive mode

The interactive mode of matplotlib is slow. If you want to visualize the calculation results on a regular basis, you want to avoid blocking the main calculation while drawing.

test.py

import numpy as np
import matplotlib.pyplot as plt
import time
import multiprocessing as mp

class Worker(object):
    def __init__(self, queue):
        self.queue = queue

    def loop(self):
        while True:
            obj = np.random.random((100, 100))
            self.queue.put(obj)
            time.sleep(1)

    def __call__(self):
        self.loop()

queue = mp.Queue()
worker = Worker(queue)
p = mp.Process(target=worker)
p.daemon = True

# initialize plot
plt.ion()
imshow = plt.imshow(np.random.random((100, 100)))
plt.show()

p.start()

while True:
    obj = queue.get()
    imshow.set_data(obj)
    plt.draw()
    plt.pause(0.0001)

Let Worker execute the calculation, and receive the calculation result through Queue and draw it every time the calculation is completed.