FuncAnimation goes past the frames argument

Question

I'm using the FuncAnimation package to make a movie of a gaussian wavepacket colliding with a potential barrier using the finite difference real-space method for solving the Schrodinger equation. The relevant code is below. Basically, when I run it, everything works well - a movie pops up showing just what I want. However, changing the "frames=" argument does not actually alter the number of frames. You can see that I print the current iteration in my animate function. This counter goes up to the number specified in "frames=", but then goes back to 0 and keeps going. The animation runs farther than specified. Even if I specify "frames=1", the movie will continue indefinitely (I tried leaving it running for an afternoon). I'm pretty stumped as to what's going on but I'm relatively sure it's something stupid.

# Set up the matplotlib figure and axes
fig = plt.figure()
ax = plt.axes(xlim = (0, hamiltonian.L), ylim = (0, 3))
line, = ax.plot([], [], lw = 2)
time_text = ax.text(.02, .95, '', transform=ax.transAxes)
ax.grid()

def init():
    """initialize the animation"""
    line.set_data([], [])
    time_text.set_text('')

    return line, time_text

def animate(i):
    """actually perform the animation"""
    print i
    global hamiltonian, wavepacket
    hamiltonian.propagate(wavepacket)
    line.set_data(wavepacket.x, wavepacket.psi_sq)
    time_text.set_text('time = %.3f' % wavepacket.time_elapsed)

    return line, time_text

# Now call the animator
anim = animation.FuncAnimation(fig, animate, init_func=init, frames=100, interval=1, blit=False)
#anim.save('gaussian_reflection.mp4', fps=150, extra_args=['-vcodec', 'libx264'])
plt.show()

Answer 1

By default the animation function loops, just use the repeat kwarg:

anim = animation.FuncAnimation(fig, animate, init_func=init, frames=100, interval=1, blit=False, repeat=False)