% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/Trend.R
\name{Trend}
\alias{Trend}
\title{Compute the trend}
\usage{
Trend(
  data,
  time_dim = "sdate",
  interval = 1,
  polydeg = 1,
  conf = TRUE,
  conf.lev = 0.95,
  ncores = NULL
)
}
\arguments{
\item{data}{An numeric array including the dimension along which the trend 
is computed.}

\item{time_dim}{A character string indicating the dimension along which to 
compute the trend. The default value is 'sdate'.}

\item{interval}{A positive numeric indicating the unit length between two 
points along 'time_dim' dimension. The default value is 1.}

\item{polydeg}{A positive integer indicating the degree of polynomial 
regression. The default value is 1.}

\item{conf}{A logical value indicating whether to retrieve the confidence 
intervals or not. The default value is TRUE.}

\item{conf.lev}{A numeric indicating the confidence level for the 
regression computation. The default value is 0.95.}

\item{ncores}{An integer indicating the number of cores to use for parallel 
computation. The default value is NULL.}
}
\value{
A list containing:
\item{$trend}{
 A numeric array with the first dimension 'stats', followed by the same 
 dimensions as parameter 'data' except the 'time_dim' dimension. The length
 of the 'stats' dimension should be \code{polydeg + 1}, containing the 
 regression coefficients from the lowest order (i.e., intercept) to the 
 highest degree.   
}
\item{$conf.lower}{
 A numeric array with the first dimension 'stats', followed by the same 
 dimensions as parameter 'data' except the 'time_dim' dimension. The length
 of the 'stats' dimension should be \code{polydeg + 1}, containing the 
 lower limit of the \code{conf.lev}\% confidence interval for all the 
 regression coefficients with the same order as \code{$trend}. Only present 
 \code{conf = TRUE}.
}
\item{$conf.upper}{
 A numeric array with the first dimension 'stats', followed by the same 
 dimensions as parameter 'data' except the 'time_dim' dimension. The length
 of the 'stats' dimension should be \code{polydeg + 1}, containing the 
 upper limit of the \code{conf.lev}\% confidence interval for all the 
 regression coefficients with the same order as \code{$trend}. Only present 
 \code{conf = TRUE}.
}
\item{$detrended}{
 A numeric array with the same dimensions as paramter 'data', containing the 
 detrended values along the 'time_dim' dimension.
}
}
\description{
Compute the linear trend or any degree of polynomial regression along the 
forecast time. It returns the regression coefficients (including the intercept)
and the confidence intervals if needed. The detrended array is also provided.\cr
The confidence interval relies on the student-T distribution.\cr\cr
}
\examples{
# Load sample data as in Load() example:
example(Load)
months_between_startdates <- 60
trend <- Trend(sampleData$obs, polydeg = 2)

}
