06a: Using Matplotlib to Create Animation

This notebooks shows how to create an animation that will run and play inside a notebook. The animation can also be written to a video file.

import matplotlib.pyplot as plt
import numpy as np
import matplotlib.animation as animation

def get_y(x, a, b, c, d):
    y = a * np.sin(b * x + c) + d
    return y

fig, ax = plt.subplots()
x = np.linspace(0, 2 * np.pi, 100)

a = 1
b = 1
c = 0
d = 0
y0 = get_y(x, a, b, c, d)

line = ax.plot(x, y0, 'b-', clip_on=False)
line = line[0]

xd = np.pi
yd = get_y(xd, a, b, c, d)
dot = ax.plot(xd, yd, 'ro', ms=10, clip_on=False)
dot = dot[0]

ax.set_xlim(0, 2 * np.pi)
ax.set_ylim(-a, a)

frames = 50

def update(i):

    dt = 2 * np.pi / frames
    c = i * dt

    # for each frame, update the data stored on each artist.
    y = get_y(x, a, b, c, d)
    line.set_xdata(x)
    line.set_ydata(y)

    yd = get_y(xd, a, b, c, d)
    dot.set_ydata([yd])

    return line,

ani = animation.FuncAnimation(fig=fig, func=update, frames=frames)
plt.close()

from IPython.display import HTML
HTML(ani.to_jshtml())

Once Loop Reflect

# the following can be used to save the animation to a file
# ext = "mp4" # mac mp4
ext = "avi" # windows avi
ani.save(f"sin_animation.{ext}")