Apply.Rd

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/Apply.R
\name{Apply}
\alias{Apply}
\title{Wrapper for Applying Atomic Functions to Arrays.}
\usage{
Apply(data, input_dims = NULL, margins = NULL, AtomicFun, ..., parallel = FALSE,
  ncores = NULL)
}
\arguments{
\item{data}{A single numeric object (vector, matrix or array) or a list of numeric objects. They must be in the same order as expected by AtomicFun.}

\item{input_dims}{List of vectors containing the dimensions to be input into AtomicFun. These vectors can contain either integers specifying the dimension position, or characters corresponding to the dimension names.}
 
\item{margins}{List of vectors containing the margins for the input objects to be split by. Or, if there is a single vector of margins specified and a list of objects in data, then the single set of margins is applied over all objects. These vectors can contain either integers specifying the dimension position, or characters corresponding to the dimension names.}

\item{AtomicFun}{Function to be applied to the arrays.}

\item{...}{Additional arguments to be used in the AtomicFun.}

\item{parallel}{Logical, should the function be applied in parallel.}

\item{ncores}{The number of cores to use for parallel computation.}
}
\value{
Array or matrix or vector resulting from AtomicFun.
}
\description{
When using a single numeric object as input, Apply is almost identical to the apply function. For multiple input objects, the output array 
will have dimensions equal to the dimensions specified in 'margins'.
}
\details{
A user can apply a function that receives 1 or more numeric objects as input, each with a different number of dimensions, and returns as a result a single array with any number of dimensions.
}
\examples{
#Change in the rate of exceedance for two arrays, with different 
#dimensions, for some matrix of exceedances.
array_1 <- array(rnorm(2000), c(10,10,20)) # array with 20 timesteps
array_2 <- array(rnorm(1000), c(10, 10, 15)) # array with 15 timesteps
thresholds <- matrix(rnorm(100), 10, 10) # matrix of thresholds (no timesteps)

# Function for calculating the change in the frequency of exceedances over the
#thresholds for array_1 relative to array_2 (percentage change).

test_fun <- function(x, y, z) {(((sum(x > z) / (length(x))) / 
                                (sum(y > z) / (length(y)))) * 100) - 100}
data = list(array_1, array_2, thresholds)
margins = list(c(1, 2), c(1, 2), c(1,2))
test <- Apply(data = data, margins = margins, AtomicFun = "test_fun")
}
\references{
Wickham, H (2011), The Split-Apply-Combine Strategy for Data Analysis, Journal of Statistical Software.
}