\name{multiecdf}
\alias{multiecdf}
\alias{multiecdf.default}
\alias{multiecdf.formula}
\alias{multiecdf.matrix}
\alias{multidensity}
\alias{multidensity.default}
\alias{multidensity.formula}
\alias{multidensity.matrix}

\title{Multiple empirical cumulative distribution functions (ecdf)
  and densities}

\description{Plot multiple empirical cumulative distribution functions (ecdf)
  and densities with user interface similar to that of \code{\link{boxplot}}.}

\usage{
multiecdf(x, \dots)
\method{multiecdf}{formula}(formula, data = NULL, xlab, na.action = NULL, \dots)
\method{multiecdf}{matrix}(x, xlab, ...) 
\method{multiecdf}{default}(x, xlim,
       col=brewer.pal(9, "Set1"),
       main="multiecdf",
       xlab,
       do.points=FALSE,
       subsample=TRUE, \dots)

multidensity(x, \dots)
\method{multidensity}{formula}(formula, data = NULL, xlab, na.action = NULL, \dots)
\method{multidensity}{matrix}(x, xlab, ...) 
\method{multidensity}{default}(x,
  bw="nrd0",
  xlim,
  ylim,
  col  = brewer.pal(9, "Set1"),
  main = "multidensity",
  xlab,
  lty  = 1L , \dots)
}

\arguments{
  \item{formula}{a formula, such as \code{y ~ grp}, where \code{y} is a
    numeric vector of data values to be split into groups according to
    the grouping variable \code{grp} (usually a factor).}
  \item{data}{a data.frame (or list) from which the variables in
    \code{formula} should be taken.}
  \item{na.action}{a function which indicates what should happen
    when the data contain \code{NA}s.  The default is to ignore missing
    values in either the response or the group.}
  \item{x}{a list of numeric vectors.}
  \item{bw}{the smoothing bandwidth, see the manual page for
    \code{\link{density}}. If \code{bw} is a character string specifying a rule to choose
    the bandwidth, this rule is applied to \code{x[[1]]} and then
    the same numerical value of \code{bw} is used throughout.}    
  \item{xlim}{Range of the x axis. If missing, the data range is used.}
  \item{ylim}{Range of the y axis. If missing, the range of the density
    estimates is used.}
  \item{col, lty}{Line colors and line type.}
  \item{main}{Plot title.}
  \item{xlab}{x-axis label.}
  \item{do.points}{logical; if \code{TRUE}, also draw points at the knot
    locations.}
   \item{subsample}{logical; if \code{TRUE}, subsamples of size 1000 are
   used to compute and plot the ecdf for list items with many
   observations (\code{>1000})} 
  \item{...}{Further arguments that get passed on to the \code{plot} functions.}
}

\seealso{
  \code{\link[graphics::boxplot]{boxplot}},
  \code{\link[stats::ecdf]{ecdf}}
  \code{\link[stats::density]{density}}
}

\details{The usefulness of \code{multidensity} can vary,
  depending on the data and because of smoothing
  artifacts. \code{multiecdf} will in many cases be preferable.}

\value{For the \code{multidensity} functions, a list of \code{\link{density}} objects.}

\author{Wolfgang Huber \url{http://www.ebi.ac.uk/huber}}

\examples{
  f = 1 + (runif(1000)>0.5)
  x = rnorm(length(f), mean=f, sd=f)
  
  multiecdf(x~f)
  multidensity(x~f)
}
\keyword{hplot}