fdPar {fda} | R Documentation |
Functional parameter objects are used as arguments to functions that
estimate functional parameters, such as smoothing functions like
smooth.basis
A functional parameter object is a functional data object along with
additional slots specifying a roughness penalty, a smoothing parameter
and whether or not the functional parameter is to be estimated or held fixed.
Functional parameter objects are used as arguments to functions that
estimate functional parameters.
fdPar(fdobj=fd(), Lfdobj=int2Lfd(0), lambda=0, estimate=TRUE, penmat=NULL)
fdobj |
a functional data object, although the argument also be a functional basis object or another functional parameter object. Basis objects are converted to functional data objects with the identity matrix as the coefficient matrix. |
Lfdobj |
either a nonnegative integer or a linear differential operator object |
lambda |
a nonnegative real number specifying the amount of smoothing to be applied to the estimated functional parameter. |
estimate |
a logical value: if TRUE , the functional parameter is
estimated, otherwise, it is held fixed.
|
penmat |
a roughness penalty matrix. Including this can eliminate the need to compute this matrix over and over again in some types of calculations. |
(p> Functional parameters are often needed to specify initial
values for iteratively refined estimates, as is the case in
functions register.fd
and smooth.monotone
.
Often a list of functional parameters must be supplied to a
function as an argument, and it may be that some of these parameters
are considered known and must remain fixed during the analysis. This
is the case for functions fRegress
and pda.fd
,
for example.
a functional parameter object
cca.fd, density.fd, fRegress, intensity.fd, pca.fd, pda.fd smooth.basis, smooth.monotone, smooth.ps
# smooth the daily temperature data with a roughness # penalty # set up the fourier basis nbasis <- 365 dayrange <- c(0,365) daybasis <- create.fourier.basis(dayrange, nbasis) dayperiod <- 365 harmaccelLfd <- vec2Lfd(c(0,(2*pi/365)^2,0), dayrange) # Make temperature fd object # Temperature data are in 12 by 365 matrix tempav # See analyses of weather data. # Set up sampling points at mid days daytime <- (1:365)-0.5 # Convert the data to a functional data object daybasis65 <- create.fourier.basis(dayrange, nbasis, dayperiod) templambda <- 1e1 tempfdPar <- fdPar(daybasis65, harmaccelLfd, templambda) #FIXME #tempfd <- smooth.basis(daily$tempav, daytime, tempfdPar) # Set up the harmonic acceleration operator Lbasis <- create.constant.basis(dayrange); Lcoef <- matrix(c(0,(2*pi/365)^2,0),1,3) bfdobj <- fd(Lcoef,Lbasis) bwtlist <- fd2list(bfdobj) harmaccelLfd <- Lfd(3, bwtlist) # Define the functional parameter object for # smoothing the temperature data lambda <- 0.01 # minimum GCV estimate #tempPar <- fdPar(daybasis365, harmaccelLfd, lambda) # smooth the data #tempfd <- smooth.basis(daytime, daily$tempav, tempPar)$fd # plot the temperature curves #plot(tempfd)