Bessel
Bessel functions
Description
    Bessel functions of the first and second kind (J, Y) and 
    modified Bessel functions of the first and second kind (I, K)
    for real nonnegative x and real order (nu).
Usage
besselJ(x, nu)
besselY(x, nu)
besselI(x, nu, expon.scaled = FALSE)
besselK(x, nu, expon.scaled = FALSE)
Arguments
| x | A numeric vector of nonnegative values. | 
| nu | A numeric vector giving the order of the Bessel function. | 
| expon.scaled | A logical value.  
    If TRUE return an exponential scale factor 
    times the value of the Bessel function, to remove the exponential growth.  
    Otherwise return the raw value of the Bessel function.
    The scale factor depends on the Bessel function:
    besselI: exp(-x),
    besselK: exp(x). | 
 
Details
Value
| besselJ, besselY | return the value of the Bessel function 
    of the first and second kind respectively. | 
| besselI, besselK | return the value of the modified Bessel function
    of the first and second kind respectively. | 
 
Differences between Spotfire Enterprise Runtime for R and Open-source R
References
Abramowitz, M. and Stegun, I. A. 1972. Chapter 9: Bessel Functions of Integer Order. Handbook of Mathematical Functions. New York, NY: Dover.
Examples
x <- seq(0, 4, length.out = 20)
besselJ(x, 1:4)
besselY(x, -1:4)
besselI(x, 10, expon.scaled = TRUE)
besselK(x, 20, expon.scaled = TRUE)