128-bit state for the PCG-XSL-RR 64-bit output generator (Melissa O'Neill). More...

#include <clustering/math/rng.h>

Public Member Functions
void	seed (std::uint64_t seedValue, std::uint64_t stream=0) noexcept
	Initialize the generator per PCG's canonical seeding procedure.

Public Attributes
__uint128_t	m_state = 0
	128-bit generator state; advanced by every `advanceState` call.
__uint128_t	m_inc = 0
	Stream-encoded odd increment mixed into the LCG step.

Detailed Description

128-bit state for the PCG-XSL-RR 64-bit output generator (Melissa O'Neill).

State and stream are held as __uint128_t. Seed with seed(seed, stream); advance via the free function advanceState(rng). Reproducibility is load-bearing: the multiplier and output function match pcg-cpp's pcg64 so identical seed + stream produce identical u64 streams across platforms that have __uint128_t.

Definition at line 30 of file rng.h.

Member Function Documentation

◆ seed()

void clustering::math::pcg64::seed	(	std::uint64_t	seedValue,
		std::uint64_t	stream = 0 )

inlinenoexcept

Initialize the generator per PCG's canonical seeding procedure.

Matches Melissa O'Neill's pcg_basic reference: zero the state, set inc to (stream << 1) | 1, advance once, add the user seed, advance once more.

Parameters

seedValue	User-supplied seed mixed into the state after the stream selector.
stream	Stream identifier; two generators with identical seed but different streams produce uncorrelated output sequences.

Definition at line 46 of file rng.h.

Member Data Documentation

◆ m_inc

__uint128_t clustering::math::pcg64::m_inc = 0

Stream-encoded odd increment mixed into the LCG step.

Definition at line 34 of file rng.h.

◆ m_state

__uint128_t clustering::math::pcg64::m_state = 0

128-bit generator state; advanced by every advanceState call.

Definition at line 32 of file rng.h.

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

include/clustering/math/rng.h