fda: register.newfd – R documentation

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fda

register.newfd

Description

This function registers a new functional data object to pre-computed warping functions.

Usage

register.newfd(yfd, Wfd,type=c('direct','monotone','periodic'))

Arguments

yfd

a multivariate functional data object defining the functions to be registered with Wfd.

Wfd

a functional data object defining the registration functions to be used to register yfd. This can be the result of either landmarkreg or register.fd.

type

indicates the type of registration function.

direct assumes Wfd is a direct definition of the registration functions. This is produced by landmarkreg.
monotone assumes that Wfd defines a monotone functional data objected, up to shifting and scaling to make endpoints agree. This is produced by register.fd.
periodic does shift registration for periodic functions. This is output from register.fd if periodic=TRUE.

Details

Only shift registration is considered for the periodic case.

Value

a functional data object defining the registered curves.

Source

Ramsay, James O., and Silverman, Bernard W. (2006), Functional Data Analysis, 2nd ed., Springer, New York.

Ramsay, James O., and Silverman, Bernard W. (2002), Applied Functional Data Analysis, Springer, New York, ch. 6 & 7.

Examples

# Register the lip data with landmark registration, then register the first
# derivatives with the pre-computed warping functions.

# Lip data:
lipfd <- smooth.basisPar(liptime, lip, 6, Lfdobj=int2Lfd(4),
                         lambda=1e-12)$fd
names(lipfd$fdnames) <- c("time(seconds)", "replications", "mm")

# Landmark Registration:

lipmeanmarks <- apply(lipmarks,2,mean)

wnbasis <- 6
wnorder <- 4
wbreaks <- c(0,lipmeanmarks,0.35)

warpbasis <- create.bspline.basis(nbasis=wnbasis, norder=wnorder,
                                  breaks=wbreaks);
WfdPar    <- fdPar(fd(basisobj=warpbasis), 2, 1e-4)

lipreglist <- landmarkreg(lipfd, as.matrix(lipmarks), lipmeanmarks, WfdPar)

# And warp:

Dlipfd = deriv.fd(lipfd,Lfdobj=1)

Dlipregfd = register.newfd(Dlipfd,lipreglist$warpfd,type='direct')

fda

Functional Data Analysis

v5.1.9

GPL (>= 2)

Authors

J. O. Ramsay <ramsay@psych.mcgill.ca> [aut,cre], Spencer Graves <spencer.graves@effectivedefense.org> [ctb], Giles Hooker <gjh27@cornell.edu> [ctb]

Initial release

2020-12-16