s18adf
s18adf
© Numerical Algorithms Group, 2002.
Purpose
S18ADF Modified Bessel function K (x)
1
Synopsis
[fun_value,ifail] = s18adf(x<,ifail>)
Description
This routine evaluates an approximation to the modified Bessel
Function of the second kind K (x).
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Note: K (x) is undefined for x<=0 and the routine will fail for
1
such arguments.
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For x near zero, K (x)~= -. This approximation is used when x is
1 x
sufficiently small for the result to be correct to machine
precision. For very small x on some machines, it is impossible to
1
calculate - without overflow and the routine must fail.
x
Parameters
s18adf
Required Input Arguments:
x real
Optional Input Arguments: <Default>
ifail integer -1
Output Arguments:
ifail integer