numpy.arctan2 () in Python

numpy.arctan2 (arr1, arr2, casting = & # 39; same_kind & # 39 ;, order = & # 39; K & # 39 ;, dtype = None, ufunc & # 39; arctan & # 39;) :
Calculates the element-wise arctangent of arr1 / arr2 by choosing the correct quadrant. The quadrant is chosen so that arctan2 (x1, x2) is the angle sign in radians between a ray ending at the origin and passing through point (1, 0) and a ray ending at the origin and passing through through point (x2) x1).

Parameters:

arr1: [array_like] real valued; y-coordinates
arr2: [array_like] real valued; x-coordinates. It must match shape of y-cordinates.
out: [ndarray, array_like [ OPTIONAL ]] array of same shape as x .
where: [array_like, optional] True value means to calculate the universal functions (ufunc) at that position, False value means to leave the value in the output alone.

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

Return: Element-wise arc tangent of arr1 / arr2. The values ​​are in the closed interval [-pi / 2, pi / 2].

Code # 1: Work

# Python3 program explaining
# arctan2 () function

 

import numpy as np

 

arr1 = [ - 1 , + 1 , + 1 , - 1 ]

arr2 = [ - 1 , - 1 , + 1 , + 1 ]

  

ans = np.arctan2 (arr2, arr1) * 180 / np.pi

 

print ( "x-coordinates:" , arr1)

print ( "y-coordin ates: " , arr2)

  

print ( "arctan2 values:" , ans)

Output:

 x-coordinates: [-1, 1, 1, -1] y-coordinates: [-1, -1, 1, 1] arctan2 values: [-135. -45. 45. 135.] 

Code # 2: Work

# Python3 program showing
# arctan2 () functions

 

import numpy as np

 

a = np.arctan2 ([ 0. , 0. , np.inf ], [ + 0. , - 0. , np.inf])

 

b = np.arctan2 ([ 1. , - 1. ], [ 0. , 0. ])

 

print ( " a : " , a)

  

print ( "b:" , b )

Output:

 a: [0. 3.14159265 0.78539816] b: [1.57079633 -1.57079633] 

Links:
https://docs.scipy.org/doc/numpy-1.13.0/reference/g enerated / numpy.arctan2.html # numpy.arctan2
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