R/besselRatio.R

In HyperbolicDist: The Hyperbolic Distribution

besselRatio <- function(x, nu, orderDiff, useExpScaled = 700){
    if (x > useExpScaled){
        besselK(x, nu + orderDiff, expon.scaled = TRUE)/
                  besselK(x, nu, expon.scaled = TRUE)
    }else{
        besselK(x, nu + orderDiff)/besselK(x, nu)
    }
}