BSI0E

This function evaluates the exponentially scaled modified Bessel function of the first kind of order zero.

Function Return Value

BSI0E — Function value. (Output)

Required Arguments

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

FORTRAN 90 Interface

Generic: BSI0E (X)

Specific: The specific interface names are S_BSI0E and D_BSI0E.

FORTRAN 77 Interface

Single: BSI0E (X)

Double: The double precision function name is DBSI0E.

Description

Function BSI0E computes e−∣x∣ I0(x). For the definition of the Bessel function I0(x), see BSI0.

Example

In this example, BSI0E(4.5) is computed and printed.

 

USE BSI0E_INT

USE UMACH_INT

 

IMPLICIT NONE

! Declare variables

INTEGER NOUT

REAL VALUE, X

! Compute

X = 4.5

VALUE = BSI0E(X)

! Print the results

CALL UMACH (2, NOUT)

WRITE (NOUT,99999) X, VALUE

99999 FORMAT (' BSI0E(', F6.3, ') = ', F6.3)

END

Output

 

BSI0E( 4.500) = 0.194