Compute the square root of negative input with emath in Python

In this article, we will cover how to compute the square root of negative inputs with emath in Python using NumPy.

Example:

Input: [-3,-4]
Output: [0.+1.73205081j 0.+2.j        ]
Explanation: Square root of a negative input.

NumPy.emath.sqrt method:

The np.emath.sqrt() method from the NumPy library calculates the square root of complex inputs. A complex value is returned for negative input elements unlike numpy.sqrt. which returns NaN.

Syntax: np.emath.sqrt()

Parameters:

• x: array like object.

Return: out: scalar or ndarray.

Example 1:

If the array contains negative input values, complex numbers are returned in the output, and the shape, datatype, and dimensions of the array can be found by .shape, .dtype, and .ndim attributes.

import numpy as np

# Creating an array
arr = np.array([-3, -4])
print(array)

# shape of the array is
print("Shape of the array is : ",arr.shape)

# dimension of the array
print("The dimension of the array is : ",arr.ndim)

# Datatype of the array
print("Datatype of our Array is : ",arr.dtype)

# computing the square root of negative inputs
print(np.emath.sqrt(arr))

Output:

[-3 -4]
Shape of the array is :  (2,)
The dimension of the array is :  1
Datatype of our Array is :  int64
[0.+1.73205081j 0.+2.j        ]

Example 2:

import numpy as np

# Creating an array
array = np.arr([complex(-2, -1),complex(-5, -3)])
print(array)

# shape of the array is
print("Shape of the array is : ",arr.shape)

# dimension of the array
print("The dimension of the array is : ",arr.ndim)

# Datatype of the array
print("Datatype of our Array is : ",arr.dtype)

# computing the square root of complex inputs
print(np.emath.sqrt(arr))

Output:

[-2.-1.j -5.-3.j]
Shape of the array is :  (2,)
The dimension of the array is :  1
Datatype of our Array is :  complex128
[0.34356075-1.45534669j 0.64457424-2.32711752j]