R: Order of a B-spline

norder {fda} | R Documentation

## Order of a B-spline

### Description

norder = number of basis functions minus the number of interior knots.

### Usage

    norder(x, ...)
    ## S3 method for class 'fd'
    norder(x, ...)
    ## S3 method for class 'basisfd'
    norder(x, ...)
    ## Default S3 method:
    norder(x, ...)

    #norder.bspline(x, ...)

    #NOTE:  The following is required by CRAN rules that
    # function names like "as.numeric" must follow the documentation
    # standards for S3 generics, even when they are not.
    # Please ignore the following line:
    ## S3 method for class 'bspline'
    norder(x, ...)

### Arguments

`x` | Either a basisfd object or an object containing a basisfd object as a component.
`...` | optional arguments currently unused

### Details

norder throws an error of basisfd[['type']] != 'bspline'.

### Value

An integer giving the order of the B-spline.

### Author(s)

Spencer Graves

### See Also

`create.bspline.basis`

### Examples

    bspl1.1 <- create.bspline.basis(norder=1, breaks=0:1)

    stopifnot(norder(bspl1.1)==1)

    stopifnot(norder(fd(0, basisobj=bspl1.1))==1)

    stopifnot(norder(fd(rep(0,4)))==4)

    stopifnot(norder(list(fd(rep(0,4))))==4)
    ## Not run:
    norder(list(list(fd(rep(0,4)))))
    Error in norder.default(list(list(fd(rep(0, 4))))) :
      input is not a 'basisfd' object and does not have a 'basisfd'
    component.

    ## End(Not run)

    stopifnot(norder(create.bspline.basis(norder=1, breaks=c(0,.5, 1))) == 1)

    stopifnot(norder(create.bspline.basis(norder=2, breaks=c(0,.5, 1))) == 2)

    # Defaut B-spline basis:  Cubic spline:  degree 3, order 4,
    # 21 breaks, 19 interior knots.
    stopifnot(norder(create.bspline.basis()) == 4)

    ## Not run:
    norder(create.fourier.basis(c(0,12) ))
    Error in norder.bspline(x) :
      object x is of type = fourier;  'norder' is only defined for type = 'bsline'

    ## End(Not run)

[Package fda version 2.4.8 Index]