primes
Fast Functions for Prime Numbers
Fast functions for dealing with prime numbers, such as testing whether a number is prime and generating a sequence prime numbers. Additional functions include finding prime factors and Ruth-Aaron pairs, finding next and previous prime numbers in the series, finding or estimating the nth prime, estimating the number of primes less than or equal to an arbitrary number, computing primorials, prime k-tuples (e.g., twin primes), finding the greatest common divisor and smallest (least) common multiple, testing whether two numbers are coprime, and computing Euler's totient function. Most functions are vectorized for speed and convenience.
Fast Functions for Prime Numbers in R
Authors: Os Keyes and Paul Egeler
License: MIT
Description
This R package has several utility functions for dealing with prime numbers, such as checking for primality and generating prime numbers. Additional functions include:
- finding prime factors and Ruth-Aaron pairs
- finding next and previous prime numbers in the series
- finding or estimating the nth prime
- estimating the number of primes less than or equal to an arbitrary number
- computing primorials
- finding prime k-tuples (e.g., twin primes)
- finding the greatest common divisor and smallest (least) common multiple
- testing whether two numbers are coprime
- computing Euler's totient (phi)
The package also provides an R dataset containing the first one thousand primes.
Installation
You can install the released version of primes from CRAN with:
install.packages("primes")
And the development version from GitHub with:
# install.packages("devtools")
devtools::install_github("ironholds/primes")
Example
This checks which of the first twenty natural numbers are prime:
library(primes)
is_prime(1:20)
## [1] FALSE TRUE TRUE FALSE TRUE FALSE TRUE FALSE FALSE FALSE TRUE FALSE TRUE FALSE
## [15] FALSE FALSE TRUE FALSE TRUE FALSE
You can also generate all the prime numbers between 101 and 199 with the following:
generate_primes(101, 199)
## [1] 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199