BEIP0

BEIP0

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

Function Return Value

BEIP0 — Function value. (Output)

Required Arguments

X — Argument for which the function value is desired. (Input)

FORTRAN 90 Interface

Generic: BEIP0 (X)

Specific: The specific interface names are S_BEIP0 and D_BEIP0.

FORTRAN 77 Interface

Single: BEIP0 (X)

Double: The double precision name is DBEIP0.

Description

The function beiʹ0(x) is defined to be

where bei0(x) is a Kelvin function, see BEI0. Function BEIP0 is based on the work of Burgoyne (1963).

If ∣x∣ > 119, then NaN (not a number) is returned.

Example

In this example, beiʹ0(0.6) is computed and printed.

USE BEIP0_INT

USE UMACH_INT

IMPLICIT NONE

! Declare variables

INTEGER NOUT

REAL VALUE, X

! Compute

X = 0.6

VALUE = BEIP0(X)

! Print the results

CALL UMACH (2, NOUT)

WRITE (NOUT,99999) X, VALUE

99999 FORMAT (' BEIP0(', F6.3, ') = ', F6.3)

END

Output

BEIP0( 0.600) = 0.300

Published date: 03/19/2020

Last modified date: 03/19/2020