Python numpy.arctan()用法及代码示例

numpy.arctan(x [，out])= ufunc'arctan')：此数学函数可帮助用户计算所有x(作为数组元素)的反切线。

参数：

array : [array_like]elements are in radians.
out   : [array_like]array of same shape as x.

Note :

2pi Radians = 360 degrees
The convention is to return the angle z whose real part lies in [-pi/2, pi/2].

返回：

An array with inverse tangent of x
for all x i.e. array elements. 

The values are in the closed interval [-pi/2, pi/2].

代码1：工作

# Python program explaining 
# arctan() function 
  
import numpy as np 
  
in_array = [0, 1, 0.3, -1] 
print ("Input array : \n", in_array) 
  
arctan_Values = np.arctan(in_array) 
print ("\nInverse Tangent values : \n", 
                            arctan_Values)

输出：

Input array : 
 [0, 1, 0.3, -1]

Inverse Tangent values : 
 [ 0.          0.78539816  0.29145679 -0.78539816]

代码2：图形表示

# Python program showing 
# Graphical representation   
# of arctan() function 
  
import numpy as np 
import matplotlib.pyplot as plt 
  
in_array = np.linspace(-np.pi, np.pi, 12) 
out_array1 = np.tan(in_array) 
out_array2 = np.arctan(in_array) 
  
print("in_array : ", in_array) 
print("\nout_array with tan : ", out_array1) 
print("\nout_arraywith arctan : ", out_array1) 
  
# red for numpy.arccos() 
plt.plot(in_array, out_array1, 
            color = 'blue', marker = "*") 
              
plt.plot(in_array, out_array2, 
            color = 'red', marker = "o") 
              
plt.title("blue : numpy.tan() \nred : numpy.arctan()") 
plt.xlabel("X") 
plt.ylabel("Y") 
plt.show()

输出：

in_array :  [-3.14159265 -2.57039399 -1.99919533 -1.42799666 -0.856798   -0.28559933
  0.28559933  0.856798    1.42799666  1.99919533  2.57039399  3.14159265]

out_array with tan :  [  1.22464680e-16   6.42660977e-01   2.18969456e+00  -6.95515277e+00
  -1.15406152e+00  -2.93626493e-01   2.93626493e-01   1.15406152e+00
   6.95515277e+00  -2.18969456e+00  -6.42660977e-01  -1.22464680e-16]

out_arraywith arctan :  [  1.22464680e-16   6.42660977e-01   2.18969456e+00  -6.95515277e+00
  -1.15406152e+00  -2.93626493e-01   2.93626493e-01   1.15406152e+00
   6.95515277e+00  -2.18969456e+00  -6.42660977e-01  -1.22464680e-16]

参考文献：
https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.arcsin.html#numpy.arccos
。