Nothing
#### Bessel functions for (very) large x/z and/or nu
#### TODO: move some stuff from ./IJKY.R to here <<<<<
### The argument range is from David Scott, for K_nu(.) case:
library(Bessel)
xs <- 100*(1:7)
nus <- 450 + 10*(0:9)
d.xn <- expand.grid(nu = nus, x = xs)
M <- with(d.xn,
cbind(K = besselK(x,nu),
K_exp = besselK(x,nu, expon.scaled = TRUE),
K_nA.2 = besselK.nuAsym(x, nu, log = TRUE, k.max=2),
K_nA.3 = besselK.nuAsym(x, nu, log = TRUE, k.max=3),
K_nA.4 = besselK.nuAsym(x, nu, log = TRUE, k.max=4))
)
## Transform into nicely labelled 3d array :
A <- M
datt <- attr(d.xn, "out.attrs")
dim(A) <- c(datt$dim, ncol(M))
dimnames(A) <- c(datt$dimnames, list(colnames(M)))
A
## Compare the different approximation levels k.max
stopifnot(
all.equal(M[,3], M[,4], tol=1e-12)# 2.826 e-13
,
all.equal(M[,4], M[,5], tol=2e-15)# 5.357 e-16
,
all.equal(M[,"K"], exp(M[,5]), tol= 1e-12)# on log.scale: 2e-16 !
)
cat('Time elapsed: ', proc.time(),'\n') # for ''statistical reasons''
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