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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/irmi.R
\name{irmi}
\alias{irmi}
\title{Iterative robust model-based imputation (IRMI)}
\usage{
irmi(
x,
eps = 5,
maxit = 100,
mixed = NULL,
mixed.constant = NULL,
count = NULL,
step = FALSE,
robust = FALSE,
takeAll = TRUE,
noise = TRUE,
noise.factor = 1,
force = FALSE,
robMethod = "MM",
force.mixed = TRUE,
mi = 1,
addMixedFactors = FALSE,
trace = FALSE,
init.method = "kNN",
modelFormulas = NULL,
multinom.method = "multinom",
imp_var = TRUE,
imp_suffix = "imp"
)
}
\arguments{
\item{x}{data.frame or matrix}
\item{eps}{threshold for convergency}
\item{maxit}{maximum number of iterations}
\item{mixed}{column index of the semi-continuous variables}
\item{mixed.constant}{vector with length equal to the number of
semi-continuous variables specifying the point of the semi-continuous
distribution with non-zero probability}
\item{count}{column index of count variables}
\item{step}{a stepwise model selection is applied when the parameter is set
to TRUE}
\item{robust}{if TRUE, robust regression methods will be applied}
\item{takeAll}{takes information of (initialised) missings in the response
as well for regression imputation.}
\item{noise}{irmi has the option to add a random error term to the imputed
values, this creates the possibility for multiple imputation. The error term
has mean 0 and variance corresponding to the variance of the regression
residuals.}
\item{noise.factor}{amount of noise.}
\item{force}{if TRUE, the algorithm tries to find a solution in any case,
possible by using different robust methods automatically.}
\item{robMethod}{regression method when the response is continuous.}
\item{force.mixed}{if TRUE, the algorithm tries to find a solution in any
case, possible by using different robust methods automatically.}
\item{mi}{number of multiple imputations.}
\item{addMixedFactors}{if TRUE add additional factor variable for each
mixed variable as X variable in the regression}
\item{trace}{Additional information about the iterations when trace equals
TRUE.}
\item{init.method}{Method for initialization of missing values (kNN or
median)}
\item{modelFormulas}{a named list with the name of variables for the rhs
of the formulas, which must contain a rhs formula for each variable with
missing values, it should look like `list(y1=c("x1","x2"),y2=c("x1","x3"))``
if factor variables for the mixed variables should be created for the
regression models}
\item{multinom.method}{Method for estimating the multinomial models
(current default and only available method is multinom)}
\item{imp_var}{TRUE/FALSE if a TRUE/FALSE variables for each imputed
variable should be created show the imputation status}
\item{imp_suffix}{suffix for the TRUE/FALSE variables showing the imputation
status}
}
\value{
the imputed data set.
}
\description{
In each step of the iteration, one variable is used as a response variable
and the remaining variables serve as the regressors.
}
\details{
The method works sequentially and iterative. The method can deal with a
mixture of continuous, semi-continuous, ordinal and nominal variables
including outliers.
A full description of the method can be found in the mentioned reference.
}
\examples{
data(sleep)
irmi(sleep)
data(testdata)
imp_testdata1 <- irmi(testdata$wna, mixed = testdata$mixed)
# mixed.constant != 0 (-10)
testdata$wna$m1[testdata$wna$m1 == 0] <- -10
testdata$wna$m2 <- log(testdata$wna$m2 + 0.001)
imp_testdata2 <- irmi(
testdata$wna,
mixed = testdata$mixed,
mixed.constant = c(-10,log(0.001))
)
imp_testdata2$m2 <- exp(imp_testdata2$m2) - 0.001
#example with fixed formulas for the variables with missing
form = list(
NonD = c("BodyWgt", "BrainWgt"),
Dream = c("BodyWgt", "BrainWgt"),
Sleep = c("BrainWgt" ),
Span = c("BodyWgt" ),
Gest = c("BodyWgt", "BrainWgt")
)
irmi(sleep, modelFormulas = form, trace = TRUE)
# Example with ordered variable
td <- testdata$wna
td$c1 <- as.ordered(td$c1)
irmi(td)
}
\references{
M. Templ, A. Kowarik, P. Filzmoser (2011) Iterative stepwise
regression imputation using standard and robust methods. \emph{Journal of
Computational Statistics and Data Analysis}, Vol. 55, pp. 2793-2806.
A. Kowarik, M. Templ (2016) Imputation with
R package VIM. \emph{Journal of
Statistical Software}, 74(7), 1-16.
}
\seealso{
\code{\link[mi:04mi]{mi::mi()}}
Other imputation methods:
\code{\link{hotdeck}()},
\code{\link{impPCA}()},
\code{\link{kNN}()},
\code{\link{matchImpute}()},
\code{\link{medianSamp}()},
\code{\link{rangerImpute}()},
\code{\link{regressionImp}()},
\code{\link{sampleCat}()}
}
\author{
Matthias Templ, Alexander Kowarik
}
\concept{imputation methods}
\keyword{manip}
|
