# [−][src]Crate primes

A basic library for finding primes, providing a basic Iterator over all primes. It is not as fast as
`slow_primes`

, but it is meant to be easy to use!

The simplest usage is simply to create an `Iterator`

:

use primes::{Sieve, PrimeSet}; let mut pset = Sieve::new(); for (ix, n) in pset.iter().enumerate().take(10) { println!("Prime {}: {}", ix, n); }

This library provides methods for generating primes, testing whether a number is prime, and factorizing numbers. Most methods generate primes lazily, so only enough primes will be generated for the given test, and primes are cached for later use.

# Example: Find the first prime after 1 million

use primes::{Sieve, PrimeSet}; let mut pset = Sieve::new(); let (ix, n) = pset.find(1_000_000); println!("Prime {}: {}", ix, n);

# Example: Find the first ten primes *after* the thousandth prime

use primes::{Sieve, PrimeSet}; let mut pset = Sieve::new(); for (ix, n) in pset.iter().enumerate().skip(1_000).take(10) { println!("Prime {}: {}", ix, n); }

# Example: Find the first prime greater than 1000

use primes::{Sieve, PrimeSet}; let mut pset = Sieve::new(); let (ix, n) = pset.find(1_000); println!("The first prime after 1000 is the {}th prime: {}", ix, n); assert_eq!(pset.find(n), (ix, n));

For more info on use, see `PrimeSet`

, a class which encapsulates most of the functionality and has
multiple methods for iterating over primes.

This also provides a few functions unconnected to `PrimeSet`

, which will be faster for the first
case, but slower in the long term as they do not use any caching of primes.

## Structs

PrimeSetIter | An iterator over generated primes. Created by |

Sieve | A prime generator, using the Sieve of Eratosthenes method. This is asymptotically more efficient than the Trial Division method, but slower earlier on. |

TrialDivision | A prime generator, using the Trial Division method. |

## Traits

PrimeSet | |

PrimeSetBasics |

## Functions

factors | Find all prime factors of a number
Does not use a |

factors_uniq | Find all unique prime factors of a number |

is_prime | Test whether a number is prime. Checks every odd number up to |