ca-traits.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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*/
 
#ifndef CA_TRAITS_H
#define CA_TRAITS_H
 
#include <array>
#include <cstddef>
#include <span>
 
namespace Aleph {
namespace CA {
 
using ca_index_t = std::ptrdiff_t;
 
using ca_size_t = std::size_t;
 
template <std::size_t N>
using Coord_Vec = std::array<ca_index_t, N>;
 
template <std::size_t N>
using Offset_Vec = Coord_Vec<N>;
 
template <typename T>
using Neighbor_View = std::span<const T>;
 
template <std::size_t Rank>
struct Cell_Context
{
  std::size_t step = 0;
  Coord_Vec<Rank> coord{};
};
 
// -----------------------------------------------------------------------
// Boundary policies
// -----------------------------------------------------------------------
 
struct OpenBoundary
{
};
 
struct ToroidalBoundary
{
};
 
struct ReflectiveBoundary
{
};
 
template <typename T, T V>
struct ConstantBoundary
{
  using state_type = T;
  static constexpr T value = V;
};
 
struct NeumannBoundary
{
};
 
// --- Phase 4 spelling aliases -----------------------------------------
//
// Phase 4 of the CA plan refers to the boundary policies as
// `Periodic`, `Reflective`, `Dirichlet<...>` and `Neumann<...>`. The
// underlying implementations are the Phase 1 tags; these aliases make
// both naming conventions available without duplicating the logic.
 
using PeriodicBoundary = ToroidalBoundary;
 
template <typename T, T V>
using DirichletBoundary = ConstantBoundary<T, V>;
 
// -----------------------------------------------------------------------
// Iteration order tags
// -----------------------------------------------------------------------
 
struct RowMajor
{
};
 
struct ColumnMajor
{
};
 
template <std::size_t W, std::size_t H>
struct Tile
{
  static_assert(W > 0 and H > 0, "Tile dimensions must be non-zero");
 
  static constexpr std::size_t width = W;
  static constexpr std::size_t height = H;
};
 
}  // namespace CA
}  // namespace Aleph
 
#endif  // CA_TRAITS_H