BEI0

This function evaluates the Kelvin function of the first kind, bei, of order zero.

Function Return Value

BEI0 — Function value. (Output)

Required Arguments

X — Argument for which the function value is desired. (Input)
ABS(X) must be less than 119.

FORTRAN 90 Interface

Generic: BEI0 (X)

Specific: The specific interface names are S_BEI0 and D_BEI0.

FORTRAN 77 Interface

Single: BEI0 (X)

Double: The double precision name is DBEI0.

Description

The Kelvin function bei0(x) is defined to be ℑJ0(xe3πi∕4). The Bessel function J0(x) is defined in BSJ0. Function BEI0 is based on the work of Burgoyne (1963).

In BEI0, x must be less than 119.

Example

In this example, bei0(0.4) is computed and printed.

 

USE BEI0_INT

USE UMACH_INT

 

IMPLICIT NONE

! Declare variables

INTEGER NOUT

REAL VALUE, X

! Compute

X = 0.4

VALUE = BEI0(X)

! Print the results

CALL UMACH (2, NOUT)

WRITE (NOUT,99999) X, VALUE

99999 FORMAT (' BEI0(', F6.3, ') = ', F6.3)

END

Output

 

BEI0( 0.400) = 0.040