How to animate a sine curve in Matplotlib?

To create an animated sine curve in Matplotlib, we use the animation module to continuously update the curve's position. This creates a smooth wave motion effect by shifting the sine wave over time.

Steps to Create Animated Sine Curve

Follow these steps to animate a sine curve −

• Set the figure size and adjust the padding between and around the subplots
• Create a new figure and add axes with appropriate limits
• Initialize an empty line plot that will be updated during animation
• Define an initialization function to reset the line data
• Create an animation function that updates the sine curve values for each frame
• Use FuncAnimation to create the animation with specified frames and interval
• Display the animated figure using show() method

Example

Here's how to create a smooth animated sine wave ?

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

# Set figure parameters
plt.rcParams["figure.figsize"] = [7.50, 3.50]
plt.rcParams["figure.autolayout"] = True

# Create figure and axes
fig = plt.figure()
ax = plt.axes(xlim=(0, 2), ylim=(-2, 2))
line, = ax.plot([], [], lw=2, color='blue')

# Add labels and title
ax.set_xlabel('X')
ax.set_ylabel('Y')
ax.set_title('Animated Sine Wave')

def init():
    """Initialize the line with empty data"""
    line.set_data([], [])
    return line,

def animate(frame):
    """Update the sine curve for each animation frame"""
    x = np.linspace(0, 2, 1000)
    y = np.sin(2 * np.pi * (x - 0.01 * frame))
    line.set_data(x, y)
    return line,

# Create animation
anim = animation.FuncAnimation(
    fig, animate, init_func=init, 
    frames=200, interval=20, blit=True
)

plt.show()

How It Works

The animation works by continuously shifting the phase of the sine wave −

• init() function: Resets the line data to empty lists before animation starts
• animate() function: Called for each frame, updates the y-values by shifting the phase
• Phase shift: The term (x - 0.01 * frame) creates the leftward motion
• FuncAnimation: Manages the animation loop with 200 frames at 20ms intervals

Parameters

Output

The animation creates a smooth sine wave that moves continuously from right to left, creating a wave motion effect.

Conclusion

Use FuncAnimation with phase shifting to create smooth animated sine curves. The blit=True parameter optimizes performance by only redrawing changed parts of the plot.