| interpSpline {splines} | R Documentation |
Create an interpolation spline, either from x and y
vectors, or from a formula/data.frame combination.
interpSpline(obj1, obj2, bSpline = FALSE, period = NULL,
na.action = na.fail)
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 NAs. 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. |
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.
Douglas Bates and Bill Venables
splineKnots,
splineOrder,
periodicSpline.
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 ) ), type = "l" ) points( women$height, women$weight ) plot( ispl ) # plots over the range of the knots points( women$height, women$weight ) splineKnots( ispl )