Concept definition

template<typename R, typename T>
concept Aleph::CA::GraphRuleLike =  CellState<T>
and (requires(const R &r, const T &s, Neighbor_View<T> v) {
       { r(s, v) } -> std::convertible_to<T>;
     }
     or requires(const R &r, const T &s, Neighbor_View<T> v,
                 const Cell_Context<1> &ctx) {
          { r(s, v, ctx) } -> std::convertible_to<T>;
        })

Detailed Description

Concept satisfied by graph rules.

A graph rule consumes the current state of a node and a span over the states of its neighbours, and produces the next state. The canonical signature is (state, Neighbor_View<state>) -> state, so any rule that already satisfies RuleLike for a rectangular lattice is reusable for graph CAs (e.g. Outer_Totalistic_Rule).

Phase 8 introduces stochastic rules that need a per-cell context to derive deterministic pseudo-random numbers. Such rules expose the alternative (state, Neighbor_View<state>, Cell_Context<1>) -> state signature; the engine routes them through apply_rule(). The graph is treated as a rank-1 lattice whose only coordinate component is the node id.

Definition at line 294 of file tpl_ca_graph_automaton.H.