>>> """
=====
Decay
=====

This example showcases:

- using a generator to drive an animation,
- changing axes limits during an animation.
"""
... 
... import itertools
... 
... import numpy as np
... import matplotlib.pyplot as plt
... 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, 10)
...     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,
... 
... ani = animation.FuncAnimation(fig, run, data_gen, interval=10, init_func=init)
... plt.show()
...