https://github.com/cran/fields
Tip revision: 292e80962d92c497484ad0735f3f13a4b8d3e0ac authored by Doug Nychka on 29 November 2007, 14:39:12 UTC
version 4.1
version 4.1
Tip revision: 292e809
find.upcross.R
"find.upcross" <-
function (fun, fun.info, upcross.level = 0, guess = 1, tol = 1e-05)
{
l1 <- guess
tr <- 0
for (k in 1:50) {
tr <- fun(l1, fun.info) - upcross.level
if (tr >= 0)
break
else {
guess <- l1
}
l1 <- l1 * 2
}
if (tr < 0) {
warning("Failed to find the upcrossing")
return(NA)
}
tr <- 0
l2 <- guess
for (k in 1:50) {
tr <- fun(l2, fun.info) - upcross.level
if (tr <= 0)
break
l2 <- l2/2
}
if (tr > 0) {
warning("Failed to find the upcrossing")
return(NA)
}
out <- bisection.search(l2, l1, fun, tol = tol, f.extra = fun.info,
upcross.level = upcross.level)$x
(out)
}