numpy.emath.sqrt

emath.sqrt(x)

Compute the square root of x.

For negative input elements, a complex value is returned (unlike numpy.sqrt which returns NaN).

Parameters:

xarray_like

The input value(s).

Returns:

outndarray or scalar

The square root of x. If x was a scalar, so is out, otherwise an array is returned.

See also

numpy.sqrt

Examples

For real, non-negative inputs this works just like numpy.sqrt:

>>> import numpy as np

>>> np.emath.sqrt(1)
1.0
>>> np.emath.sqrt([1, 4])
array([1.,  2.])

But it automatically handles negative inputs:

>>> np.emath.sqrt(-1)
1j
>>> np.emath.sqrt([-1,4])
array([0.+1.j, 2.+0.j])

Different results are expected because: floating point 0.0 and -0.0 are distinct.

For more control, explicitly use complex() as follows:

>>> np.emath.sqrt(complex(-4.0, 0.0))
2j
>>> np.emath.sqrt(complex(-4.0, -0.0))
-2j