ValueError：形状不匹配：无法将对象广播到单个形状。 不匹配在 arg 0 与形状 (48000,) 和 arg 1 与形状 (2,) 之间

Question

I tried to animate a simple (sine)^3 fucntion using PillowWriter, but stuck with this error. Belowmentioned is my code for the same:

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

def y(x):
    z = 3 * np.sin(x)**3
    return z

fig = plt.figure()
l, = plt.plot([], [], 'g-')

plt.xlim(-12,12)
plt.ylim(-12,12)

metadata = dict(title="3[sin(x)]^3", artist="Me")
writer = PillowWriter(fps=20, metadata=metadata)

x_axis = np.arange(-12, 12, 0.0005)
y_axis = []

with writer.saving(fig, "y(x).gif", 100):
    for x in x_axis:
        y_axis.append(y(x))

        l.set_data(x_axis, y_axis)
        writer.grab_frame()

Answer 1

It seems that your y_axis is not long enough, so the plot does not know how to compare it to the x_axis array. I would suggest the following solution:

from matplotlib.axis import XAxis
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.animation import PillowWriter

def y(x):
    z = 3 * np.sin(x)**3
    return z

fig = plt.figure()
l, = plt.plot([], [], 'g-')

plt.xlim(-12,12)
plt.ylim(-12,12)

metadata = dict(title="3[sin(x)]^3", artist="Me")
writer = PillowWriter(fps=20, metadata=metadata)

x_axis = np.arange(-12, 12, 0.05) # 0.0005 causes performance issues
y_axis = np.zeros(len(x_axis))

with writer.saving(fig, "y(x).gif", 100):
    for n, x_val in enumerate(x_axis):
        y_axis[n] = y(x_val)
        l.set_data(x_axis, y_axis)
        writer.grab_frame()

Explanation: It creates a y_axis array which is of equal length as the x_axis array, but is filled with zeros. Then, for each frame, it counts and sets the next value of the y_axis array equal to the function value. Note: I reduced the resolution of the x_axis array because it was giving me performance issues.