Scaled modified Bessel function of the second kind, order n.
Loading LOADSUB ALL FROM "BESMC.HTS"
or LOADSUB FROM "MATHLIB.HTS"
Usage INTEGER N
REAL X,Y
Y=FNKne(N,X)
Description
FNKnereturns the value of the modified cylindrical Bessel function of the second kind and ordernofxscaled byex,exKn(x). AlthoughexKn(x) is defined for all positive values ofx, values ofxnear zero may cause the absolute value of the result to be larger than MAXREAL, the largest value representable. The scaling is done so that the value ofKn(x) can be evaluated for arguments of large absolute value, where the value ofKn(x) may be near zero.
Errors
FNKnecauses an HTBasic error if its arguments are not of the types listed in the USAGE section, above, ifxis not positive, or if the result would be larger than MAXREAL.
exKn(x)
See Also I0e, In, K0e, K1e, Kn
Note
The algorithm used computes the value ofKnusing a recursion from the values ofK0 andK1. The computation time increases withnand the computation accuracy decreases withn.