Matplotlib multiProcessing

Question

I am trying to make it so that I can run an infinite loop asking for user input as well as running a matplotlib simple diagram. Any suggestions how this can work? Currently I have for my code:

def createGraph():
 fig = plt.figure()
 fig.suptitle('A Graph ', fontsize=14, fontweight='bold')

 ax = fig.add_subplot(111)
 fig.subplots_adjust(top=.9)

 ax.set_xlabel('X Score')
 ax.set_ylabel('Y Score')
 plt.plot([1,2,3,4,5,6,7],[1,3,3,4,5,6,7], 'ro')
 plt.show()

def sub_proc(q,fileno):
 sys.stdin = os.fdopen(fileno)  #open stdin in this process
 some_str = ""
 while True:
    some_str = raw_input("> ")

    if some_str.lower() == "quit":
        return
    q.put_nowait(some_str)

if __name__ == "__main__":
    q = Queue()
    fn = sys.stdin.fileno() #get original file descriptor
    qproc = Process(target=sub_proc, args=(q,fn))
    qproc.start()
    qproc.join()
    zproc = Process(target=createGraph)
    zproc.start()
    zproc.join()

As you see, I am trying to get processes to get this to work, so the code works in parallel. Ultimately, I would like to get it so that a user can display a graph, while at the same time being able to input in the console. Thanks for any help!!

Answer 1

Is this what you want?

import matplotlib.pyplot as plt
import numpy as np

if __name__ == "__main__":
    fig, ax = plt.subplots(1, 1)
    theta = np.linspace(0, 2*np.pi, 1024)
    ln, = ax.plot(theta, np.sin(theta))

    plt.ion()
    plt.show(block=False)
    while True:
        w = raw_input("enter omega: ")
        try:
            w = float(w)
        except ValueError:
            print "you did not enter a valid float, try again"
            continue
        y = np.sin(w * theta)
        ln.set_ydata(y)
        plt.draw()

I think I was sending you down a much too complicated path in the comments