splinefun(x, y, method="fmm") spline (x, y, n=3*length(x), method="fmm", xmin=min(x), xmax=max(x))
x,y
| vectors giving the coordinates of the points to be interpolated. Alternatively a single plotting structure can be specified. |
method
|
specifies the type of spline to be used.
Possible values are "fmm" , "natural" and "periodic" .
|
n
|
interpolation takes place at n
equally spaced points spanning the interval [xmin, xmax] .
|
xmin
| left-hand endpoint of the interpolation interval. |
xmax
| right-hand endpoint of the interpolation interval. |
spline
performs cubic spline interpolation of the given data points.
It returns a list containing components
x
, and y
which give the ordinates where interpolation took
place and the interpolated values.
splinefun
returns a function which will perform
cubic spline interpolation of the given data points.
This is often more useful than spline
.
If method="fmm"
, the spline used is that of
Forsythe, Malcolm and Moler (an exact cubic is fitted through
the four points at each end of the data, and this is used
to determine the end conditions).
Natural splines are used when
method="natural"
and periodic splines when
method="periodic"
.
approx
and approxfun
for constant and linear
interpolation.