% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/forecast2.R
\name{croston}
\alias{croston}
\title{Forecasts for intermittent demand using Croston's method}
\usage{
croston(y, h = 10, alpha = 0.1, x = y)
}
\arguments{
\item{y}{a numeric vector or time series of class \code{ts}}

\item{h}{Number of periods for forecasting.}

\item{alpha}{Value of alpha. Default value is 0.1.}

\item{x}{Deprecated. Included for backwards compatibility.}
}
\value{
An object of class \code{"forecast"} is a list containing at least
the following elements: \item{model}{A list containing information about the
fitted model. The first element gives the model used for non-zero demands.
The second element gives the model used for times between non-zero demands.
Both elements are of class \code{forecast}.} \item{method}{The name of the
forecasting method as a character string} \item{mean}{Point forecasts as a
time series} \item{x}{The original time series (either \code{object} itself
or the time series used to create the model stored as \code{object}).}
\item{residuals}{Residuals from the fitted model. That is y minus fitted
values.} \item{fitted}{Fitted values (one-step forecasts)}

The function \code{summary} is used to obtain and print a summary of the
results, while the function \code{plot} produces a plot of the forecasts.

The generic accessor functions \code{fitted.values} and \code{residuals}
extract useful features of the value returned by \code{croston} and
associated functions.
}
\description{
Returns forecasts and other information for Croston's forecasts applied to
y.
}
\details{
Based on Croston's (1972) method for intermittent demand forecasting, also
described in Shenstone and Hyndman (2005). Croston's method involves using
simple exponential smoothing (SES) on the non-zero elements of the time
series and a separate application of SES to the times between non-zero
elements of the time series. The smoothing parameters of the two
applications of SES are assumed to be equal and are denoted by \code{alpha}.

Note that prediction intervals are not computed as Croston's method has no
underlying stochastic model.
}
\examples{
y <- rpois(20,lambda=.3)
fcast <- croston(y)
plot(fcast)

}
\references{
Croston, J. (1972) "Forecasting and stock control for
intermittent demands", \emph{Operational Research Quarterly}, \bold{23}(3),
289-303.

Shenstone, L., and Hyndman, R.J. (2005) "Stochastic models underlying
Croston's method for intermittent demand forecasting". \emph{Journal of
Forecasting}, \bold{24}, 389-402.
}
\seealso{
\code{\link{ses}}.
}
\author{
Rob J Hyndman
}
\keyword{ts}