BSK0
This function evaluates the modified Bessel function of the second kind of order zero.
Function Return Value
BSK0 — Function value. (Output)
Required Arguments
X — Argument for which the function value is desired. (Input)
Fortran 90 Interface
Generic: BSK0 (X)
Specific: The specific interface names are S_BSK0 and D_BSK0.
FORTRAN 77 Interface
Single: BSK0 (X)
Double: The double precision function name is DBSK0.
Description
The Bessel function K0(x) is defined to be
The argument must be larger than zero, but not so large that the result, approximately equal to
underflows.
Figure 14, Plot of K0(x) and K1(x)
Comments
Informational Error
Type | Code | Description |
|---|---|---|
2 | 1 | The function underflows because X is too large. |
Example
In this example, K0(0.5) is computed and printed.
USE BSK0_INT
USE UMACH_INT
IMPLICIT NONE
! Declare variables
INTEGER NOUT
REAL VALUE, X
! Compute
X = 0.5
VALUE = BSK0(X)
! Print the results
CALL UMACH (2, NOUT)
WRITE (NOUT,99999) X, VALUE
99999 FORMAT (' BSK0(', F6.3, ') = ', F6.3)
END
Output
BSK0( 0.500) = 0.924
