BSK1E

This function evaluates the exponentially scaled modified Bessel function of the second kind of order one.

Function Return Value

BSK1E — Function value. (Output)

Required Arguments

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

FORTRAN 90 Interface

Generic: BSK1E (X)

Specific: The specific interface names are S_BSK1E and D_BSK1E.

FORTRAN 77 Interface

Single: BSK1E (X)

Double: The double precision function name is DBSK1E.

Description

Function BSK1E computes exK1(x). For the definition of the Bessel function K1(x), see BSK1. The answer BSK1E = exK1(x) ≈ 1/x overflows if x is too close to zero.

Example

In this example, BSK1E(0.5) is computed and printed.

 

USE BSK1E_INT

USE UMACH_INT

 

IMPLICIT NONE

! Declare variables

INTEGER NOUT

REAL VALUE, X

! Compute

X = 0.5

VALUE = BSK1E(X)

! Print the results

CALL UMACH (2, NOUT)

WRITE (NOUT,99999) X, VALUE

99999 FORMAT (' BSK1E(', F6.3, ') = ', F6.3)

END

Output

 

BSK1E( 0.500) = 2.731