scipy.special.kei#
- scipy.special.kei(x, out=None) = <ufunc 'kei'>#
- Kelvin function kei. - Defined as \[\mathrm{kei}(x) = \Im[K_0(x e^{\pi i / 4})]\]- where \(K_0\) is the modified Bessel function of the second kind (see - kv). See [dlmf] for more details.- Parameters:
- xarray_like
- Real argument. 
- outndarray, optional
- Optional output array for the function results. 
 
- Returns:
- scalar or ndarray
- Values of the Kelvin function. 
 
 - See also - References [dlmf]- NIST, Digital Library of Mathematical Functions, https://dlmf.nist.gov/10.61 - Examples - It can be expressed using the modified Bessel function of the second kind. - >>> import numpy as np >>> import scipy.special as sc >>> x = np.array([1.0, 2.0, 3.0, 4.0]) >>> sc.kv(0, x * np.exp(np.pi * 1j / 4)).imag array([-0.49499464, -0.20240007, -0.05112188, 0.0021984 ]) >>> sc.kei(x) array([-0.49499464, -0.20240007, -0.05112188, 0.0021984 ])