smooth.fd {fda}R Documentation

Smooth a Functional Data Object Using a Roughness Penalty


This function is intended to apply a roughness penalized smooth to data already set up as a functional data object. For example, data may have been converted to a functional data object using function data2fd using a fairly large set of basis functions, and subsequently it was desired to smooth the functional data object that resulted.


smooth.fd(fd, lambda=0, Lfd=NULL, rebase=TRUE)


fd The functional data object to be smoothed.
lambda A nonnegative value controlling the amount of roughness in the data.
Lfd Either a nonnegative integer or a linear differential operator object. If present, the derivative or the value of applying the operator is evaluated rather than the functions themselves.
rebase A logical variable that is only relevant if the basis is a polygonal basis of type "polyg". If this case, if rebase is TRUE , then the basis is changed to a cubic bspline basis before smoothing.


See function smooth.basis for details.


A functional data object.




A discussion of roughness penalties can be found in Chapter 4 of Ramsay, J. O. and Silverman, B.W. (1997) Functional Data Analysis. More information can be found in recent texts on nonparametric regression.

See Also

data2fd, plotfit.fd, smooth.basis, project.basis


[Package fda version 1.0 Index]