1"""
2=====
3Decay
4=====
5
6This example showcases:
7- using a generator to drive an animation,
8- changing axes limits during an animation.
9"""
10
11import numpy as np
12import matplotlib.pyplot as plt
13import matplotlib.animation as animation
14
15
16def data_gen(t=0):
17    cnt = 0
18    while cnt < 1000:
19        cnt += 1
20        t += 0.1
21        yield t, np.sin(2*np.pi*t) * np.exp(-t/10.)
22
23
24def init():
25    ax.set_ylim(-1.1, 1.1)
26    ax.set_xlim(0, 10)
27    del xdata[:]
28    del ydata[:]
29    line.set_data(xdata, ydata)
30    return line,
31
32fig, ax = plt.subplots()
33line, = ax.plot([], [], lw=2)
34ax.grid()
35xdata, ydata = [], []
36
37
38def run(data):
39    # update the data
40    t, y = data
41    xdata.append(t)
42    ydata.append(y)
43    xmin, xmax = ax.get_xlim()
44
45    if t >= xmax:
46        ax.set_xlim(xmin, 2*xmax)
47        ax.figure.canvas.draw()
48    line.set_data(xdata, ydata)
49
50    return line,
51
52ani = animation.FuncAnimation(fig, run, data_gen, blit=False, interval=10,
53                              repeat=False, init_func=init)
54plt.show()
55