Decaying oscillation

The animation module provides an Animation class to clean up the creation of animated plots. This class is built on top of matplotlib’s animation subpackage, which was introduced in matplotlib v.1.1.

import numpy as np
import matplotlib.pyplot as plt

from mpltools.animation import Animation


class DecayingOscillation(Animation):

    def __init__(self, L=2*np.pi, npts=100, num_periods=5, decay_rate=0.1):
        self.fig, self.ax = plt.subplots(figsize=(4, 4))
        self.x = np.linspace(0, L, npts)
        self.num_periods = num_periods
        self.decay_rate = decay_rate
        # Note: If `num_frames` not defined, # of saved frames defaults to 100.
        self.num_frames = 500

    def update(self):
        self.line, = self.ax.plot(self.x, np.sin(self.x))
        tmax = self.num_periods * 2*np.pi
        for t in np.linspace(0, tmax, self.num_frames):
            amplitude = np.exp(-t * self.decay_rate) * np.cos(t)
            self.line.set_ydata(amplitude * np.sin(self.x))
            # must return list of artists if you want to use blit
            yield self.line,


osc = DecayingOscillation()
osc.animate(blit=True)

# Note: `save` and `show` don't play nice together. Use one at a time.
#osc.save('decaying_oscillation.avi', fps=30, bitrate=200)
plt.show()

Python source code: download (generated using mpltools 0.2dev)