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