Python 类 __call__ 函数未矢量化

Question

I am trying to plot a function using the __call__ dunder for a custom class

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

class F:
    def __init__(self, n, m):
        self._n = n
        self._m = m

    def __call__(self, x):
        return math.sin(self._n * x) * math.cos(self._m * x)

u = F(1,1)
v = F(1,1)

x_array = np.linspace(0, 2*np.pi, 20)

u_array = u(x_array)
v_array = v(x_array)

plt.plot(u_array, v_array)
plt.show()

However, executing the code, i get this error

Traceback (most recent call last):
  File "F.py", line 18, in <module>
    u_array = u(x_array)
  File "F.py", line 11, in __call__
    return math.sin(self._n * x) * math.cos(self._m * x)
TypeError: only size-1 arrays can be converted to Python scalars

It seems that the call u_array = u(x_array) sends the entire x_array to the function, instead of doing it in a vectorized way.

Please help

Answer 1

Use the numpy vectorized functions instead of those from math :

def __call__(self, x):
    return np.sin(self._n * x) * np.cos(self._m * x)