https://github.com/cran/pracma
Tip revision: 26e049d70b4a1c237987e260cba68f6a9413736c authored by Hans W. Borchers on 09 April 2019, 04:10:07 UTC
version 2.2.5
version 2.2.5
Tip revision: 26e049d
pchip.R
##
## p c h i p . R Test suite
##
pchip <- pracma::pchip
x <- c(1, 2, 3, 4, 5, 6)
y <- c(16, 18, 21, 17, 15, 12)
xs <- c(1.5, 2.5, 3.5, 4.5, 5.5)
ys <- pchip(x, y, xs)
# ys <- interp1(x, y, xs, method="cubic") # the same
# 16.88750 19.80000 19.33333 15.96667 13.63750
yml <- c(16.887499999999999, 19.800000000000001, 19.333333333333332,
15.966666666666667, 13.637499999999999)
all.equal(ys, yml, tolerance = 1e-7)