Aleph::CA::Probabilistic_Rule< F, Engine > Class Template Reference

Reproducible stochastic rule wrapper (Phase 8). More...

#include <tpl_ca_rule.H>

Public Types
using	engine_type = Engine
	Underlying engine type used when the wrapped functor accepts an Engine& reference.

Public Member Functions
constexpr	Probabilistic_Rule (F func)
	Construct a stochastic wrapper from a functor.
constexpr	Probabilistic_Rule (F func, std::uint64_t master_seed)
	Construct a stochastic wrapper with an explicit master seed.
constexpr std::uint64_t	master_seed () const noexcept
void	set_master_seed (std::uint64_t s) noexcept
	Replace the master seed without rebuilding the rule.
template<typename State > requires std::invocable<F &, const State &, Neighbor_View<State>>
State	operator() (const State &current, Neighbor_View< State > neighbours) const
	Legacy invocation: forward (state, neighbours) to F.
template<typename State , std::size_t Rank>
State	operator() (const State &current, Neighbor_View< State > neighbours, const Cell_Context< Rank > &ctx) const
	Reproducible invocation with engine context.

Private Attributes
F	f_
std::uint64_t	master_seed_ = 0

Detailed Description

template<typename F, typename Engine = std::mt19937_64>
class Aleph::CA::Probabilistic_Rule< F, Engine >

Reproducible stochastic rule wrapper (Phase 8).

Probabilistic_Rule<F, Engine> accepts two functor flavours:

• Legacy: F(State, Neighbor_View<State>) -> State. Random sources are managed by the functor; the rule simply forwards the call. This is the Phase 0–7 behaviour.
• Reproducible: F(State, Neighbor_View<State>, Engine&) -> State. The rule receives a Cell_Context<Rank> from the engine, derives a per-cell seed via cell_seed(master_seed, ctx), builds a fresh Engine and hands it by reference to F. Two runs with the same (master_seed, initial frame) are bit-for-bit identical regardless of the number of worker threads.

Both invocation modes coexist on the same class, so a rule that was already a Probabilistic_Rule<F> keeps compiling without changes.

Template Parameters

F	functor type accepting one of the two signatures above.
Engine	RNG engine handed to reproducible functors. Defaults to std::mt19937_64.

Definition at line 348 of file tpl_ca_rule.H.

Member Typedef Documentation

engine_type

template<typename F , typename Engine = std::mt19937_64>

using Aleph::CA::Probabilistic_Rule< F, Engine >::engine_type = Engine

Underlying engine type used when the wrapped functor accepts an Engine& reference.

Definition at line 356 of file tpl_ca_rule.H.

Constructor & Destructor Documentation

Probabilistic_Rule() [1/2]

template<typename F , typename Engine = std::mt19937_64>

constexpr Aleph::CA::Probabilistic_Rule< F, Engine >::Probabilistic_Rule ( F  func )

inlineexplicitconstexpr

Construct a stochastic wrapper from a functor.

Backwards-compatible 1-argument form: the master seed defaults to 0 and is only consulted when the functor opts in to the reproducible signature.

Parameters

[in]

func

callable object satisfying one of the two signatures described above.

Exceptions

Any	exception thrown while moving/copying func.

Definition at line 368 of file tpl_ca_rule.H.

Probabilistic_Rule() [2/2]

template<typename F , typename Engine = std::mt19937_64>

constexpr Aleph::CA::Probabilistic_Rule< F, Engine >::Probabilistic_Rule ( F  func, std::uint64_t  master_seed  )

inlineconstexpr

Construct a stochastic wrapper with an explicit master seed.

Parameters

[in]	func	callable object accepting (State, Neighbor_View<State>, Engine&).
[in]	master_seed	root seed forwarded to cell_seed(master_seed, ctx) for every cell.

Exceptions

Any	exception thrown while moving/copying func.

Definition at line 378 of file tpl_ca_rule.H.

Member Function Documentation

master_seed()

template<typename F , typename Engine = std::mt19937_64>

constexpr std::uint64_t Aleph::CA::Probabilistic_Rule< F, Engine >::master_seed ( ) const

inlineconstexprnoexcept

Returns

the master seed currently used to derive per-cell streams.

Definition at line 383 of file tpl_ca_rule.H.

References Aleph::CA::Probabilistic_Rule< F, Engine >::master_seed_.

operator()() [1/2]

template<typename F , typename Engine = std::mt19937_64>

template<typename State >
requires std::invocable<F &, const State &, Neighbor_View<State>>

State Aleph::CA::Probabilistic_Rule< F, Engine >::operator() ( const State &  current, Neighbor_View< State >  neighbours  ) const

inline

Legacy invocation: forward (state, neighbours) to F.

Template Parameters

State

cell state type.

Parameters

[in]	current	current centre-cell state.
[in]	neighbours	read-only neighbour values.

Returns

next state produced by the wrapped functor.

Exceptions

Any	exception thrown by the wrapped functor.

Definition at line 400 of file tpl_ca_rule.H.

References Aleph::CA::Probabilistic_Rule< F, Engine >::f_.

operator()() [2/2]

template<typename F , typename Engine = std::mt19937_64>

template<typename State , std::size_t Rank>

State Aleph::CA::Probabilistic_Rule< F, Engine >::operator() ( const State &  current, Neighbor_View< State >  neighbours, const Cell_Context< Rank > &  ctx  ) const

inline

Reproducible invocation with engine context.

When F accepts an Engine&, the rule constructs an engine seeded with cell_seed(master_seed_, ctx) and forwards it. When F only accepts the legacy 2-argument signature, the call is forwarded as-is and ctx is ignored.

Template Parameters

State	cell state type.
Rank	lattice rank carried by ctx.

Parameters

[in]	current	current centre-cell state.
[in]	neighbours	read-only neighbour values.
[in]	ctx	per-cell context provided by the engine.

Returns

next state produced by the wrapped functor.

Exceptions

Any	exception thrown by the wrapped functor.

Definition at line 423 of file tpl_ca_rule.H.

References Aleph::blossom_maximum_cardinality_matching(), Aleph::CA::Probabilistic_Rule< F, Engine >::f_, and Aleph::CA::Probabilistic_Rule< F, Engine >::master_seed_.

set_master_seed()

template<typename F , typename Engine = std::mt19937_64>

void Aleph::CA::Probabilistic_Rule< F, Engine >::set_master_seed ( std::uint64_t  s )

inlinenoexcept

Replace the master seed without rebuilding the rule.

Definition at line 389 of file tpl_ca_rule.H.

References Aleph::CA::Probabilistic_Rule< F, Engine >::master_seed_.

Member Data Documentation

f_

template<typename F , typename Engine = std::mt19937_64>

F Aleph::CA::Probabilistic_Rule< F, Engine >::f_

mutableprivate

Definition at line 350 of file tpl_ca_rule.H.

Referenced by Aleph::CA::Probabilistic_Rule< F, Engine >::operator()(), and Aleph::CA::Probabilistic_Rule< F, Engine >::operator()().

master_seed_

template<typename F , typename Engine = std::mt19937_64>

std::uint64_t Aleph::CA::Probabilistic_Rule< F, Engine >::master_seed_ = 0

private

Definition at line 351 of file tpl_ca_rule.H.

Referenced by Aleph::CA::Probabilistic_Rule< F, Engine >::master_seed(), Aleph::CA::Probabilistic_Rule< F, Engine >::operator()(), and Aleph::CA::Probabilistic_Rule< F, Engine >::set_master_seed().

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

• tpl_ca_rule.H