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shiny/man/repeatable.Rd
2012-10-24 16:12:08 -07:00

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R

\name{repeatable}
\alias{repeatable}
\title{Make a random number generator repeatable}
\usage{
repeatable(rngfunc,
seed = runif(1, 0, .Machine$integer.max))
}
\arguments{
\item{rngfunc}{The function that is affected by the R
session's seed.}
\item{seed}{The seed to set every time the resulting
function is called.}
}
\value{
A repeatable version of the function that was passed in.
}
\description{
Given a function that generates random data, returns a
wrapped version of that function that always uses the
same seed when called. The seed to use can be passed in
explicitly if desired; otherwise, a random number is
used.
}
\note{
When called, the returned function attempts to preserve
the R session's current seed by snapshotting and
restoring \code{\link[base]{.Random.seed}}.
}
\examples{
rnormA <- repeatable(rnorm)
rnormB <- repeatable(rnorm)
rnormA(3) # [1] 1.8285879 -0.7468041 -0.4639111
rnormA(3) # [1] 1.8285879 -0.7468041 -0.4639111
rnormA(5) # [1] 1.8285879 -0.7468041 -0.4639111 -1.6510126 -1.4686924
rnormB(5) # [1] -0.7946034 0.2568374 -0.6567597 1.2451387 -0.8375699
}