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
