A crate for generating and working with prime numbers in const contexts.
#![no_std] compatible.
Generate arrays of prime numbers with the function primes which uses a segmented sieve of Eratosthenes.
rust
const PRIMES: [u32; 10] = primes();
assert_eq!(PRIMES[5], 13);
assert_eq!(PRIMES, [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]);
or with the type Primes which ensures that a non-zero number of primes are generated:
rust
const PRIMES: Primes<10> = Primes::new();
assert_eq!(PRIMES[5], 13);
assert_eq!(PRIMES, [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]);
It also lets you reuse it as a cache of primes for related computations:
```rust
const CACHE: Primes<100> = Primes::new();
// For primality testing
const CHECK42: Option
// Or for prime counting
const PRIMESLEQ100: Option
// If questions are asked about numbers
// outside the cache it returns None
assert!(CACHE.isprime(1000).isnone());
assert!(CACHE.countprimesleq(1000).is_none());
``
Creating aPrimes<0>` is a compile fail in const contexts and a panic otherwise.
Use are_prime to compute the prime status of all integers below a given value
rust
const PRIME_STATUS: [bool; 10] = are_prime();
// 0 1 2 3 4 5 6 7 8 9
assert_eq!(PRIME_STATUS, [false, false, true, true, false, true, false, true, false, false]);
or is_prime to test whether a given number is prime
rust
const CHECK: bool = is_prime(2_147_483_629);
assert!(CHECK);
or prime_counts to count the number of primes less than or equal to each index of an array
rust
const COUNTS: [usize; 10] = prime_counts();
assert_eq!(COUNTS, [0, 0, 1, 2, 2, 3, 3, 4, 4, 4]);
Licensed under either of
at your option.
Contributions are welcome!
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.