Crux::RandomEngine Class Reference

High-performance 64-bit state, 32-bit output PRNG based on PCG32. More...

#include <RandomEngine.h>

Public Member Functions
	RandomEngine () noexcept
	Default constructor initializes state and stream to constants.
void	Seed (u64 initState, u64 initseq) noexcept
	Seeds the generator with explicit state and sequence values.
u32	Next () noexcept
	Generates the next 32-bit pseudorandom number.
u32	Next (u32 min, u32 max) noexcept
	Generates a 32-bit integer uniformly in [min, max).
u32	Next (u32 max) noexcept
	Generates a 32-bit integer uniformly in [0, max).
f32	NextFloat () noexcept
	Generates a f32ing-point number uniformly in [0.0, 1.0).
f32	NextFloat (f32 min, f32 max) noexcept
	Generates a f32 uniformly in [min, max).
f32	NextFloat (f32 max) noexcept
	Generates a f32 uniformly in [0.0, max).

Detailed Description

High-performance 64-bit state, 32-bit output PRNG based on PCG32.

Uses a Linear Congruential Generator (LCG) to advance a 64-bit state, then applies an xorshift and bit-rotation to produce a 32-bit pseudorandom result.

Constructor & Destructor Documentation

RandomEngine()

Crux::RandomEngine::RandomEngine ( )

inlinenoexcept

Default constructor initializes state and stream to constants.

Member Function Documentation

Next() [1/3]

u32 Crux::RandomEngine::Next ( )

inlinenoexcept

Generates the next 32-bit pseudorandom number.

Advances the internal 64-bit state then applies the PCG output transformation: xorshifted = ((oldstate >> 18) ^ oldstate) >> 27; rot = oldstate >> 59; result = rotate_right(xorshifted, rot);

Returns

32-bit unsigned pseudorandom value.

Next() [2/3]

u32 Crux::RandomEngine::Next ( u32 max )

inlinenoexcept

Generates a 32-bit integer uniformly in [0, max).

Parameters

max	Exclusive upper bound.

Returns

Pseudorandom integer in [0, max).

Next() [3/3]

u32 Crux::RandomEngine::Next ( u32 min, u32 max )

inlinenoexcept

Generates a 32-bit integer uniformly in [min, max).

Parameters

min	Inclusive lower bound.
max	Exclusive upper bound.

Returns

Pseudorandom integer in [min, max). Returns min if min >= max.

NextFloat() [1/3]

f32 Crux::RandomEngine::NextFloat ( )

inlinenoexcept

Generates a f32ing-point number uniformly in [0.0, 1.0).

Scales Next() output by 1/2^32.

Returns

f32 in [0.0f, 1.0f).

NextFloat() [2/3]

f32 Crux::RandomEngine::NextFloat ( f32 max )

inlinenoexcept

Generates a f32 uniformly in [0.0, max).

Parameters

max	Exclusive upper bound.

Returns

f32 in [0.0f, max).

NextFloat() [3/3]

f32 Crux::RandomEngine::NextFloat ( f32 min, f32 max )

inlinenoexcept

Generates a f32 uniformly in [min, max).

Parameters

min	Inclusive lower bound.
max	Exclusive upper bound.

Returns

f32 in [min, max). Returns min if min >= max.

Seed()

void Crux::RandomEngine::Seed ( u64 initState, u64 initseq )

inlinenoexcept

Seeds the generator with explicit state and sequence values.

Proper seeding procedure ensures avoidance of the all-zero state:

1. Sets state to zero and increment to (initseq << 1) | 1.
2. Advances one step.
3. Mixes initState into state.
4. Advances again.

Parameters

initState	64-bit initial state seed.
initseq	64-bit sequence seed (stream selector).

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The documentation for this class was generated from the following file:

• Crux/src/Crux/Random/RandomEngine.h