K = besselk(alpha,x)K = besselk(alpha,x,1)
K = besselk(alpha,x) computes modified Bessel functions of the second kind for real, non-negative order alpha and argument x. If alpha is a scalar and x is a vector, K is a vector the same length as x. If x is a vector of length m and alpha is a vector of length n, then K is an m-by-n matrix and K(i,k) is besselk(alpha(k), x(i)). The elements of x can be any nonnegative real values, in any order. For alpha, the increment between elements must be 1, and all elements must be between 0 and 1000, inclusive.
The relationship between K and the ordinary Bessel functions J and Y is
K = besselk(alpha,x,1) computes besselk(alpha,x).*exp(-x).
besselk algorithm is based on a FORTRAN program by W.J. Cody and L. Stoltz, Applied Mathematics Division, Argonnne National Laboratory, dated May 30, 1989.
bessel,besseli,besselj,bessely
(c) Copyright 1994 by The MathWorks, Inc.