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 (unsigned long long initState, unsigned long long initseq) noexcept
	Seeds the generator with explicit state and sequence values.
unsigned int	Next () noexcept
	Generates the next 32-bit pseudorandom number.
unsigned int	Next (unsigned int min, unsigned int max) noexcept
	Generates a 32-bit integer uniformly in [min, max).
unsigned int	Next (unsigned int max) noexcept
	Generates a 32-bit integer uniformly in [0, max).
float	NextFloat () noexcept
	Generates a floating-point number uniformly in [0.0, 1.0).
float	NextFloat (float min, float max) noexcept
	Generates a float uniformly in [min, max).
float	NextFloat (float max) noexcept
	Generates a float 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]

unsigned int 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]

unsigned int Crux::RandomEngine::Next ( unsigned int 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]

unsigned int Crux::RandomEngine::Next ( unsigned int min, unsigned int 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]

float Crux::RandomEngine::NextFloat ( )

inlinenoexcept

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

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

Returns

Float in [0.0f, 1.0f).

NextFloat() [2/3]

float Crux::RandomEngine::NextFloat ( float max )

inlinenoexcept

Generates a float uniformly in [0.0, max).

Parameters

max	Exclusive upper bound.

Returns

Float in [0.0f, max).

NextFloat() [3/3]

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

inlinenoexcept

Generates a float uniformly in [min, max).

Parameters

min	Inclusive lower bound.
max	Exclusive upper bound.

Returns

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

Seed()

void Crux::RandomEngine::Seed ( unsigned long long initState, unsigned long long 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