Struct Rand32

pub struct Rand32 { /* private fields */ }

A PRNG producing a 32-bit output.

The current implementation is PCG-XSH-RR.

Implementations

impl Rand32

pub const DEFAULT_INC: u64 = 1_442_695_040_888_963_407u64

The default value for increment. This is basically arbitrary, it comes from the PCG reference C implementation: https://github.com/imneme/pcg-c/blob/master/include/pcg_variants.h#L284

pub fn new(seed: u64) -> Self

Creates a new PRNG with the given seed and a default increment.

pub fn new_inc(seed: u64, increment: u64) -> Self

Creates a new PRNG. The two inputs, seed and increment, determine what you get; increment basically selects which sequence of all those possible the PRNG will produce, and the seed selects where in that sequence you start.

Both are arbitrary; increment must be an odd number but this handles that for you

pub fn state(&self) -> (u64, u64)

Returns the internal state of the PRNG. This allows you to save a PRNG and create a new one that will resume from the same spot in the sequence.

pub fn from_state(state: (u64, u64)) -> Self

Creates a new PRNG from a saved state from Rand32::state(). This is NOT quite the same as new_inc() because new_inc() does a little extra setup work to initialize the state.

pub fn rand_u32(&mut self) -> u32

Produces a random u32 in the range [0, u32::MAX].

pub fn rand_i32(&mut self) -> i32

Produces a random i32 in the range [i32::MIN, i32::MAX].

pub fn rand_float(&mut self) -> f32

Produces a random f32 in the range [0.0, 1.0).

pub fn rand_range(&mut self, range: Range<u32>) -> u32

Produces a random within the given bounds. Like any Range, it includes the lower bound and excludes the upper one.

This should be faster than Self::rand() % end + start, but the real advantage is it’s more convenient. Requires that range.end <= range.start.

Trait Implementations

impl Clone for Rand32

fn clone(&self) -> Rand32

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Rand32

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

Formats the value using the given formatter.

impl PartialEq for Rand32

fn eq(&self, other: &Rand32) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Rand32

impl StructuralPartialEq for Rand32