kelvinKei0Derivative¶

Evaluates the derivative of the Kelvin function of the second kind, kei, of order zero.

Synopsis¶

kelvinKei0Derivative (x)

Required Arguments¶

float x (Input): Argument for which the function value is desired.

Return Value¶

The derivative of the Kelvin function of the second kind, kei, of order zero evaluated at x.

Description¶

The function $\text{kei}'_0(x)$ is defined to be

$\frac{d}{dx} \mathrm{kei}_0(x)$

The function kelvinKei0Derivative is based on the work of Burgoyne (1963).

If $x<0$ , NaN (Not a Number) is returned. If $x\geq 119$ , zero is returned.

Example¶

In this example, $\text{kei}'_0(0.6)$ is evaluated.

from __future__ import print_function
from numpy import *
from pyimsl.math.kelvinKei0Derivative import kelvinKei0Derivative

x = 0.6
ans = kelvinKei0Derivative(x)
print("kei0'(0.6) = %f" % (ans))

Output¶

kei0'(0.6) = 0.348164