[−][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 |