kelvin_kei0

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

Synopsis

#include <imsl.h>

float imsl_f_kelvin_kei0 (float x)

The type double function is imsl_d_kelvin_kei0.

Required Arguments

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

Return Value

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

Description

The modified Kelvin function kei0(x) is defined to be ℑK0(xeπ/4). The Bessel function K0(x) is defined

 

The function imsl_f_kelvin_kei0 is based on the work of Burgoyne (1963). If x < 0, NaN (Not a Number) is returned. If x ≥ 119, zero is returned.

Example

In this example, kei0(0.4) is evaluated.

 

#include <imsl.h>

#include <stdio.h>

 

int main()

{

float x = 0.4;

float ans;

 

x = imsl_f_kelvin_kei0 (x);

printf ("kei0(0.4) = %f\n", x);

}

Output

 

kei0(0.4) = -0.703800