Create an Interpolation Spline
Usage
interpSpline(obj1, obj2, bSpline, period, na.action)
Arguments
obj1
|
Either a numeric vector of x values or a formula.
|
obj2
|
If obj1 is numeric this should be a numeric vector
of the same length. If obj1 is a formula this can be an
optional data frame in which to evaluate the names in the formula.
|
bSpline
|
If TRUE the b-spline representation is returned,
otherwise the piecewise polynomial representation is returned.
Defaults to FALSE .
|
period
|
An optional positive numeric value giving a period for a
periodic interpolation spline.
|
na.action
|
a optional function which indicates what should happen
when the data contain NA s. The default action
(na.omit ) is to omit any incomplete observations. The
alternative action na.fail causes interpSpline to print
an error message and terminate if there are any incomplete
observations.
|
Description
Create an interpolation spline, either from x
and
y
vectors, or from a formula/data.frame combination.Value
An object that inherits from class spline
. The object can be in
the B-spline representation, in which case it will be of class
nbSpline
for natural B-spline, or in the piecewise polynomial
representation, in which case it will be of class npolySpline
.Author(s)
Douglas Bates and Bill VenablesSee Also
splineKnots
,
splineOrder
,
periodicSpline
Examples
library( splines )
data( women )
ispl <- interpSpline( women$height, women$weight )
ispl2 <- interpSpline( weight ~ height, women )
# ispl and ispl2 should be the same
plot( predict( ispl, seq( 55, 75, len = 51 ) ) )
plot( ispl ) # plots over the range of the knots
splineKnots( ispl )