Aleph::CA::Lookup_Rule< NumStates, NumNeighbors > Class Template Reference

Precomputed transition table for (self, neighbours...). More...

#include <tpl_ca_rule.H>

Collaboration diagram for Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >:

Public Types
using	table_type = std::array< std::size_t, table_size_v >
	Transition table type storing next states for every input tuple.

Public Member Functions
constexpr	Lookup_Rule ()=default
	Build a zero-initialised lookup rule.
constexpr	Lookup_Rule (table_type t)
	Build a lookup rule from a precomputed transition table.
constexpr const table_type &	raw_table () const noexcept
	Return the underlying transition table.
template<typename State >
State	operator() (const State &current, Neighbor_View< State > neighbours) const
	Compute the next state using the precomputed table.

Static Public Attributes
static constexpr std::size_t	num_states_v = NumStates
	Number of distinct cell states accepted by this rule.
static constexpr std::size_t	num_neighbours_v = NumNeighbors
	Number of neighbour entries required by operator().
static constexpr std::size_t	table_size_v = ca_rule_detail::static_pow_rule(NumStates, NumNeighbors + 1)
	Number of entries in the transition table.

Private Attributes
table_type	table_ {}

Detailed Description

template<std::size_t NumStates, std::size_t NumNeighbors>
class Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >

Precomputed transition table for (self, neighbours...).

For S states and K neighbours, the table size is S^(K+1). The index used to look up the next state is

idx = self * S^K + neighbours[0] * S^(K-1) + ... + neighbours[K-1]

which matches the canonical "self-major" convention. The factory make_wolfram_elementary_rule(rule_no) translates the standard Wolfram code (which uses a different bit layout) into a table for this convention assuming the neighbourhood used at the call site is Custom_Neighborhood<1, 2>{ {-1, +1} } — i.e. left first, right second.

Template Parameters

NumStates	number of distinct cell states.
NumNeighbors	number of neighbours seen by the rule.

Definition at line 212 of file tpl_ca_rule.H.

Member Typedef Documentation

table_type

template<std::size_t NumStates, std::size_t NumNeighbors>

using Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::table_type = std::array<std::size_t, table_size_v>

Transition table type storing next states for every input tuple.

Definition at line 226 of file tpl_ca_rule.H.

Constructor & Destructor Documentation

Lookup_Rule() [1/2]

template<std::size_t NumStates, std::size_t NumNeighbors>

constexpr Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::Lookup_Rule ( )

constexprdefault

Build a zero-initialised lookup rule.

Every transition maps to state 0.

Lookup_Rule() [2/2]

template<std::size_t NumStates, std::size_t NumNeighbors>

constexpr Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::Lookup_Rule ( table_type  t )

inlineexplicitconstexpr

Build a lookup rule from a precomputed transition table.

Parameters

[in]

t

transition table indexed by (self, neighbours...).

Exceptions

Any	exception thrown while copying/moving the table.

Definition at line 243 of file tpl_ca_rule.H.

Member Function Documentation

operator()()

template<std::size_t NumStates, std::size_t NumNeighbors>

template<typename State >

State Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::operator() ( const State &  current, Neighbor_View< State >  neighbours  ) const

inline

Compute the next state using the precomputed table.

Template Parameters

State

cell state type convertible to std::size_t.

Parameters

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

Returns

next state stored in the table.

Exceptions

std::length_error	if neighbours.size() != NumNeighbors.
std::domain_error	if current or a neighbour is outside [0, NumStates).

Definition at line 266 of file tpl_ca_rule.H.

References ah_domain_error_if, ah_length_error_if, Aleph::blossom_maximum_cardinality_matching(), Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::table_, and value.

raw_table()

template<std::size_t NumStates, std::size_t NumNeighbors>

constexpr const table_type & Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::raw_table ( ) const

inlineconstexprnoexcept

Return the underlying transition table.

Returns

const reference to the rule table.

Exceptions

This	function does not throw.

Definition at line 250 of file tpl_ca_rule.H.

References Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::table_.

Member Data Documentation

num_neighbours_v

template<std::size_t NumStates, std::size_t NumNeighbors>

constexpr std::size_t Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::num_neighbours_v = NumNeighbors

staticconstexpr

Number of neighbour entries required by operator().

Definition at line 219 of file tpl_ca_rule.H.

num_states_v

template<std::size_t NumStates, std::size_t NumNeighbors>

constexpr std::size_t Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::num_states_v = NumStates

staticconstexpr

Number of distinct cell states accepted by this rule.

Definition at line 216 of file tpl_ca_rule.H.

table_

template<std::size_t NumStates, std::size_t NumNeighbors>

table_type Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::table_ {}

private

Definition at line 229 of file tpl_ca_rule.H.

Referenced by Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::operator()(), and Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::raw_table().

table_size_v

template<std::size_t NumStates, std::size_t NumNeighbors>

constexpr std::size_t Aleph::CA::Lookup_Rule< NumStates, NumNeighbors >::table_size_v = ca_rule_detail::static_pow_rule(NumStates, NumNeighbors + 1)

staticconstexpr

Number of entries in the transition table.

Definition at line 222 of file tpl_ca_rule.H.

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

• tpl_ca_rule.H