问matplotlib动画不会动画正弦函数

EN

l = 0.5
k = (2 * np.pi)/l
f = 4
w = 2 * np.pi * f
y = np.sin(k * x + w * i)

y = np.sin(15*x - 62 * i)

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


fig = plt.figure()
ax = plt.axes(xlim=(0, 2), ylim=(-2, 2))
line, = ax.plot([], [], lw=2)

# initialization function
def init():
    line.set_data([], [])
    return line,

# animation function
def animate(i):
    x = np.linspace(0, 2, 1000)
    l = 0.5
    k = (2 * np.pi)/l
    f = 4
    w = 2 * np.pi * f
    y = np.sin(k * x + w * i)
    #y = np.sin(15*x - 62 * i)
    line.set_data(x, y)
    return line,


anim = animation.FuncAnimation(fig, animate, init_func=init,
                               frames=300, interval=20, blit=True)


anim.save('basic_animation.mp4', fps=30, extra_args=['-vcodec', 'libx264'])

plt.show()