Struct PCG32

pub struct PCG32 {
    pub state: u64,
    pub inc: u64,
}

A Permuted Congruential Generator with 32-bit output.

• Period: 2**64 when inc is odd, otherwise less

Fields

state: u64

The generator’s state.

This changes with each step of the generator. It’s the generator’s “position” within the output stream.

inc: u64

The generator’s increment.

This doesn’t change as the generator advances. Instead it determines which of the possible output streams the generator will use. Each inc value will give a different ordering of all the possible outputs.

Implementations

impl PCG32

pub const fn new(state: u64, inc: u64) -> Self

Creates a new generator by directly using the value given.

When a raw state value is selected manually, the initial output of the generator will frequently be 0. If the initial state is not from a randomization source then you should probably call seed instead.

pub const fn seed(seed: u64, inc: u64) -> Self

Seed a new generator.

pub fn from_getrandom() -> Result<Self, Error>

Available on crate feature getrandom only.

Create a new generator seeded with data from getrandom.

This method ensures that the inc of the new generator is odd.

pub fn next_u32(&mut self) -> u32

Generate the next u32 in the sequence.

pub fn jump(&mut self, delta: u64)

Jump the generator the given number of steps forward in the sequence.

This can go x steps forward in only about log2(x) time.

Because the sequence is a loop, you can go “back” by x steps just by passing x.wrapping_neg() to go sufficiently far forward.

Trait Implementations

impl Clone for PCG32

fn clone(&self) -> PCG32

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PCG32

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Gen32 for PCG32

fn next_u32(&mut self) -> u32

Makes the generator create the next output.

fn next_i32(&mut self) -> i32

Gives a uniformly distributed value.

fn next_bool(&mut self) -> bool

Gives a uniformly distributed value.

fn next_f32_unit(&mut self) -> f32

Gives a value in the range 0.0 ..= 1.0

fn d4(&mut self) -> i32

Gives a value in the range 1 ..= 4

fn d6(&mut self) -> i32

Gives a value in the range 1 ..= 6

fn d8(&mut self) -> i32

Gives a value in the range 1 ..= 8

fn d10(&mut self) -> i32

Gives a value in the range 1 ..= 10

fn d12(&mut self) -> i32

Gives a value in the range 1 ..= 12

fn d20(&mut self) -> i32

Gives a value in the range 1 ..= 20