AKERP0
This function evaluates the derivative of the Kelvin function of the second kind, ker, of order zero.
Function Return Value
AKERP0 — Function value. (Output)
Required Arguments
X — Argument for which the function value is desired. (Input)
It must be nonnegative.
FORTRAN 90 Interface
Generic: AKERP0 (X)
Specific: The specific interface names are S_AKERP0 and D_AKERP0.
FORTRAN 77 Interface
Single: AKERP0 (X)
Double: The double precision name is DKERP0.
Description
The function kerʹ0(x) is defined to be
where ker
0(
x) is a Kelvin function, see
AKER0. Function
AKERP0 is based on the work of Burgoyne (1963). If
x < 0, then NaN (not a number) is returned. If
x > 119, then zero is returned.
Example
In this example, kerʹ0(0.6) is computed and printed.
USE AKERP0_INT
USE UMACH_INT
IMPLICIT NONE
! Declare variables
INTEGER NOUT
REAL VALUE, X, AKERP0
! Compute
X = 0.6
VALUE = AKERP0(X)
! Print the results
CALL UMACH (2, NOUT)
WRITE (NOUT,99999) X, VALUE
99999 FORMAT (' AKERP0(', F6.3, ') = ', F6.3)
END
Output
AKERP0( 0.600) = -1.457
