https://github.com/cran/pracma
Tip revision: 392ae21a013fb3f518e8f9eb8efb458a55a2eca2 authored by HwB on 09 April 2011, 00:00:00 UTC
version 0.3-0
version 0.3-0
Tip revision: 392ae21
isprime.Rd
\name{isprime}
\alias{isprime}
\title{isprime Property}
\description{
Vectorized version, returning for a vector or matrix of positive integers
a vector of the same size containing 1 for the elements that are prime and
0 otherwise.
}
\usage{
isprime(x)
}
\arguments{
\item{x}{vector or matrix of nonnegative integers}
}
\details{
Given an array of positive integers returns an array of the same size
of 0 and 1, where the i indicates a prime number in the same position.
}
\value{
array of elements 0, 1 with 1 indicating prime numbers
}
\author{
hwb \email{hwborchers@googlemail.com}
}
\seealso{
\code{\link{ifactor}, \link{primes}}
}
\examples{
x <- matrix(1:10, nrow=10, ncol=10, byrow=TRUE)
x * isprime(x)
# Find first prime number octett:
octett <- c(0, 2, 6, 8, 30, 32, 36, 38) - 19
while (TRUE) {
octett <- octett + 210
if (all(as.logical(isprime(octett)))) {
cat(octett, "\n", sep=" ")
break
}
}
}
\keyword{ math }