IMSL_KELVIN_KER0
The KELVIN_KERO function evaluates the Kelvin function of the second kind, ker, of order zero.
This routine requires an IDL Advanced Math and Stats license. For more information, contact your sales or technical support representative.
The modified Kelvin function ker0(x) is defined to be ¬K0(xepi/4). The Bessel function K0(x) is defined:
If the keyword DERIVATIVE is set, the function ker0′(x) is defined to be:
If x < 0, NaN (Not a Number) is returned. If x ≥ 119, then zero is returned.
The IMSL_KELVIN_KER0 function is based on the work of Burgoyne (1963).
Example
In this example, ker0(0.4) and ker0′(0.6) are evaluated.
PRINT, IMSL_KELVIN_KER0(0.4)
1.06262
PRINT, IMSL_KELVIN_KER0(0.6, /DERIVATIVE)
-1.45654
Syntax
Result = IMSL_KELVIN_KER0(X [, DERIVATIVE=value] [, /DOUBLE])
Return Value
The value of the Kelvin function of the second kind, ker, of order zero evaluated at x.
Arguments
X
Argument for which the function value is desired.
Keywords
DERIVATIVE (optional)
If present and nonzero, then the derivative of the Kelvin function of the second kind, ker, of order zero evaluated at x is computed.
DOUBLE (optional)
If present and nonzero, then double precision is used.
Version History
|
6.4 |
Introduced |