"""

=====

Decay

=====

This example showcases:

- using a generator to drive an animation,

- changing axes limits during an animation.

Output generated via `matplotlib.animation.Animation.to_jshtml`.

"""

import itertools

import matplotlib.pyplot as plt

import numpy as np

import matplotlib.animation as animation

def data_gen():

for cnt in itertools.count():

t = cnt / 10

yield t, np.sin(2*np.pi*t) * np.exp(-t/10.)

def init():

ax.set_ylim(-1.1, 1.1)

ax.set_xlim(0, 1)

del xdata[:]

del ydata[:]

line.set_data(xdata, ydata)

return line,

fig, ax = plt.subplots()

line, = ax.plot([], [], lw=2)

ax.grid()

xdata, ydata = [], []

def run(data):

# update the data

t, y = data

xdata.append(t)

ydata.append(y)

xmin, xmax = ax.get_xlim()

if t >= xmax:

ax.set_xlim(xmin, 2*xmax)

ax.figure.canvas.draw()

line.set_data(xdata, ydata)

return line,

# Only save last 100 frames, but run forever

ani = animation.FuncAnimation(fig, run, data_gen, interval=100, init_func=init,

save_count=100)

plt.show()