| bspline {hero} | R Documentation |
B-spline specification
Description
bspline helps define the parameters necessary for
constructing a B-spline but doesn't evaluate it.
Usage
bspline(rangeval = 0:1, nbasis, nknots, norder = 4, extend = FALSE, knots)
Arguments
rangeval |
A numeric vector of length 2 defining the
interval over which the functional data object can be
evaulated. The default value is |
nbasis |
An integer specifying the number of
basis functions to construct. This is closely linked to
the number of knots ( |
nknots |
The number of *interior* knots. See Details. |
norder |
An integer specifying the order of the B-splines, which is one higher than their degree. The default is 4, which corresponds to cubic splines. |
extend |
Should the knots stop at the endpoints specified by |
knots |
A numeric vector with all knots (interior and exterior), including potentially replicated endpoints. See Details. |
Details
The knots are assumed to be equidistant and non-repeating (except possibly at the endpoints).
The number of knots (nknots) and the number of
basis function (nbasis) are linked by the relation
nknots = nbasis - norder.
If extend = TRUE, the interior knots are
augmented by replicating the rangeval endpoints
norder times. Otherwise, the interior knots are
augmented by norder knots at each end
corresponding to the spacing of the interior knots.
The knot placement mimics the behavior of
create.bspline.basis when extend
= FALSE. Note that the number of breaks specified by
breaks in create.bspline.basis
corresponds to the number of interior knots plus 2 (the
interior knots plus the two endpoints).
If knots is specified, the function does minimial
argument checking. This is provided (mostly) for
testing purposes, though it can be used by individuals
who want more customizability of knots locations than
the equidistant spacing provided by default.
Value
An object of class hero_bspline. It is a
list specifying the necessary B-spline parameters.
Author(s)
Joshua French
See Also
Examples
bspline(nbasis = 10)