R: Fourier Basis Function Values

fourier {fda} | R Documentation

## Fourier Basis Function Values

### Description

Evaluates a set of Fourier basis functions, or a derivative of these functions, at a set of arguments.

### Usage

    fourier(x, nbasis=n, period=span, nderiv=0)

### Arguments

`x` | a vector of argument values at which the Fourier basis functions are to be evaluated.
`nbasis` | the number of basis functions in the Fourier basis. The first basis function is the constant function, followed by sets of sine/cosine pairs. Normally the number of basis functions will be an odd. The default number is the number of argument values.
`period` | the width of an interval over which all sine/cosine basis functions repeat themselves. The default is the difference between the largest and smallest argument values.
`nderiv` | the derivative to be evaluated. The derivative must not exceed the order. The default derivative is 0, meaning that the basis functions themselves are evaluated.

### Value

a matrix of function values. The number of rows equals the number of arguments, and the number of columns equals the number of basis functions.

### See Also

`fourierpen`

### Examples

    #  set up a set of 11 argument values
    x <- seq(0,1,0.1)
    names(x) <- paste("x", 0:10, sep="")
    #  compute values for five Fourier basis functions
    #  with the default period (1) and derivative (0)
    (basismat <- fourier(x, 5))

    # Create a false Fourier basis, i.e., nbasis = 1
    # = a constant function
    fourier(x, 1)

[Package fda version 2.4.8 Index]