Block-based local rules for Aleph::CA (Phase 13). More...

#include <array>
#include <concepts>
#include <cstddef>
#include <type_traits>
#include <utility>

Include dependency graph for tpl_ca_block_rule.H:

This graph shows which files directly or indirectly include this file:

Classes
class	Aleph::CA::Critters_Rule
	Critters reversible CA block rule. More...

class	Aleph::CA::BBM_Rule
	Fredkin–Toffoli Billiard Ball Machine block rule. More...

class	Aleph::CA::TM_Gas_Rule
	Toffoli–Margolus (TM) lattice-gas block rule. More...

class	Aleph::CA::Cell_Rule_As_Block_Rule< Cell_Rule >
	Adapt a regular cell rule (with empty neighborhood) to a block rule. More...

Namespaces
namespace	Aleph
	Main namespace for Aleph-w library functions.

namespace	Aleph::CA

namespace	Aleph::CA::ca_block_rule_detail

Concepts
concept	Aleph::CA::Block_Rule_2x2
	A rule that maps a 2×2 block to a 2×2 block.

Typedefs
template<typename State >
using	Aleph::CA::Block_2x2 = std::array< State, 4 >
	Fixed-size 2×2 block of cell values used by Margolus rules.

Functions
template<typename State >
constexpr State	Aleph::CA::ca_block_rule_detail::invert (const State &s) noexcept
	Toggle a cell value between its zero and a non-zero counterpart.

template<typename State >
constexpr std::size_t	Aleph::CA::ca_block_rule_detail::popcount (const Block_2x2< State > &b) noexcept
	Population count of a 2×2 block: number of non-zero cells.

Detailed Description

Block-based local rules for Aleph::CA (Phase 13).

Where a RuleLike rule consumes (state, neighbours) and returns one cell value, a block rule consumes a fixed-size block of cell values and returns the new block in one shot. Block rules are the natural fit for the Margolus update (tpl_ca_update_scheme.H): the partition decides which 2×2 cells form the active block, and the rule rewrites those four cells atomically.

The bundled rules cover the canonical reversible automata:

Critters_Rule — invert population if popcount != 2, then rotate the block 180°. Reversible because both invert and rotate-180 are involutions.
BBM_Rule — Fredkin & Toffoli's Billiard Ball Machine logic.
TM_Gas_Rule — Toffoli–Margolus lattice gas (variant of BBM that conserves particles and momentum).
Cell_Rule_As_Block_Rule<R> — adaptor that wraps a regular cell rule (whose neighbourhood is empty) as a block rule.

Convention for the 2×2 block array:

index 0 = NW (top-left)     index 1 = NE (top-right)
index 2 = SW (bottom-left)  index 3 = SE (bottom-right)

Author: Leandro Rabindranath Leon

Definition in file tpl_ca_block_rule.H.

Classes

Namespaces

Concepts

Typedefs

Functions

Detailed Description