Returns for a vector or matrix of positive integers a logical object of the same dimension(s) containing TRUE for the elements that are prime and FALSE otherwise.
IsPrime(x)vector or matrix of nonnegative integers
logical vector
Given a vector or a matrix of positive integers returns a vector of the same size
of FALSE and TRUE. Use which(IsPrime(1:21)) to get the positions.
# NOT RUN {
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(IsPrime(octett))) {
cat(octett, "\n", sep=" ")
break
}
}
# }
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