I finally found the answer: the easiest way to enforce this is just
removing the 2 knots, like this:
## thanks for all those who replied to the increasing sequences questions
incseq <- function(a,b) {
if (a <= b)
seq.int(from=a,to=b)
else
integer(0)
}
## remove & augment knots
extendk
Hi,
I would like to fit an (interpolating) spline to data where the
derivatives at the endpoints of the interval are nonzero, thus the
natural spline endpoint-specification does not make sense. Books (de
Boor, etc) suggest that in this case I use not-a-knot splines.
I know what not-a-knot spline
