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% File nlme/man/reStruct.Rd
% Part of the nlme package for R
% Distributed under GPL 2 or later: see nlme/LICENCE.note
\name{reStruct}
\title{Random Effects Structure}
\usage{
reStruct(object, pdClass, REML, data)
\method{print}{reStruct}(x, sigma, reEstimates, verbose, \dots)
}
\alias{reStruct}
\alias{[.reStruct}
\alias{print.reStruct}
\arguments{
\item{object}{any of the following: (i) a one-sided formula of the form
\code{~x1+...+xn | g1/.../gm}, with \code{x1+...+xn} specifying the
model for the random effects and \code{g1/.../gm} the grouping
structure (\code{m} may be equal to 1, in which case no \code{/} is
required). The random effects formula will be repeated for all levels
of grouping, in the case of multiple levels of grouping; (ii) a list of
one-sided formulas of the form \code{~x1+...+xn | g}, with possibly
different random effects models for each grouping level. The order of
nesting will be assumed the same as the order of the elements in the
list; (iii) a one-sided formula of the form \code{~x1+...+xn}, or a
\code{pdMat} object with a formula (i.e. a non-\code{NULL} value for
\code{formula(object)}), or a list of such formulas or \code{pdMat}
objects. In this case, the grouping structure formula will be derived
from the data used to to fit the mixed-effects model, which should
inherit from class \code{groupedData}; (iv) a named list of formulas or
\code{pdMat} objects as in (iii), with the grouping factors as
names. The order of nesting will be assumed the same as the order of
the order of the elements in the list; (v) an \code{reStruct} object.}
\item{pdClass}{an optional character string with the name of the
\code{pdMat} class to be used for the formulas in
\code{object}. Defaults to \code{"pdLogChol"} which corresponds to a
general positive-definite matrix (Log-Cholesky parametrization).}
\item{REML}{an optional logical value. If \code{TRUE}, the associated
mixed-effects model will be fitted using restricted maximum
likelihood; else, if \code{FALSE}, maximum likelihood will be
used. Defaults to \code{FALSE}.}
\item{data}{an optional data frame in which to evaluate the variables
used in the random effects formulas in \code{object}. It is used to
obtain the levels for \code{factors}, which affect the dimensions and
the row/column names of the underlying \code{pdMat} objects. If
\code{NULL}, no attempt is made to obtain information on
\code{factors} appearing in the formulas. Defaults to the
parent frame from which the function was called.}
\item{x}{an object inheriting from class \code{reStruct} to be printed.}
\item{sigma}{an optional numeric value used as a multiplier for
the square-root factors of the \code{pdMat} components (usually the
estimated within-group standard deviation from a mixed-effects
model). Defaults to 1.}
\item{reEstimates}{an optional list with the random effects estimates
for each level of grouping. Only used when \code{verbose = TRUE}.}
\item{verbose}{an optional logical value determining if the random
effects estimates should be printed. Defaults to \code{FALSE}.}
\item{\dots}{Optional arguments can be given to other methods for this
generic. None are used in this method.}
}
\description{
This function is a constructor for the \code{reStruct} class,
representing a random effects structure and consisting of a list of
\code{pdMat} objects, plus a \code{settings} attribute containing
information for the optimization algorithm used to fit the associated
mixed-effects model.
}
\value{
an object inheriting from class \code{reStruct}, representing a random
effects structure.
}
\author{José Pinheiro and Douglas Bates \email{bates@stat.wisc.edu}}
\seealso{
\code{\link{groupedData}},
\code{\link{lme}},
\code{\link{pdMat}},
\code{\link{solve.reStruct}},
\code{\link{summary.reStruct}},
\code{\link{update.reStruct}}
}
\examples{
rs1 <- reStruct(list(Dog = ~day, Side = ~1), data = Pixel)
rs1 # 2 entries "Uninitialized"
str(rs1) # a bit more
}
\keyword{models}
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