fdata.deriv: Computes the derivative of functional data object.

In fda.usc: Functional Data Analysis and Utilities for Statistical Computing

Computes the derivative of functional data object.

Description

Computes the derivative of functional data.

• If method ="bspline", "exponential", "fourier", "monomial" or "polynomial". fdata.deriv function creates a basis to represent the functional data. The functional data are converted to class fd using the Data2fd function and the basis indicated in the method. Finally, the function calculates the derivative of order nderiv of curves using deriv.fd function.
  

• If method="fmm", "periodic", "natural" or "monoH.FC" is used splinefun function.

• If method="diff", raw derivation is applied. Not recommended to use this method when the values are not equally spaced.
  

Usage

fdata.deriv(
  fdataobj,
  nderiv = 1,
  method = "bspline",
  class.out = "fdata",
  nbasis = NULL,
  ...
)

Arguments

fdataobj	fdata class object.
nderiv	Order of derivation, by defalult nderiv=1.
method	Type of derivative method, for more information see details.
class.out	Class of functional data returned: fdata or fd class.
nbasis	Number of Basis for fdatataobj\$DATA. It is only used if method ="bspline", "exponential", "fourier", "monomial" or "polynomial"
...	Further arguments passed to or from other methods.

Value

Returns the derivative of functional data of fd class if class.out="fd" or fdata class if class.out="fdata".

See Also

See also deriv.fd, splinefun and fdata

Examples

data(tecator)
absorp=tecator$absorp.fdata
tecator.fd1=fdata2fd(absorp)
tecator.fd2=fdata2fd(absorp,"fourier",9)
tecator.fd3=fdata2fd(absorp,"fourier",nbasis=9,nderiv=1)
#tecator.fd1;tecator.fd2;tecator.fd3
tecator.fdata1=fdata(tecator.fd1)
tecator.fdata2=fdata(tecator.fd2)
tecator.fdata3=fdata(tecator.fd3)
tecator.fdata4=fdata.deriv(absorp,nderiv=1,method="bspline",
class.out='fdata',nbasis=9)
tecator.fd4=fdata.deriv(tecator.fd3,nderiv=0,class.out='fd',nbasis=9)
plot(tecator.fdata4)
plot(fdata.deriv(absorp,nderiv=1,method="bspline",class.out='fd',nbasis=11))

fda.usc documentation built on Oct. 17, 2022, 9:06 a.m.