ca_engine_sync_test.cc

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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
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  copies of the Software, and to permit persons to whom the Software is
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# include <array>
# include <initializer_list>
# include <set>
# include <span>
# include <utility>
# include <vector>
 
# include <gtest/gtest.h>
 
# include <ca-traits.H>
# include <tpl_ca_storage.H>
# include <tpl_ca_lattice.H>
# include <tpl_ca_neighborhood.H>
# include <tpl_ca_rule.H>
# include <tpl_ca_engine.H>
# include <ca-engine-utils.H>
 
using namespace Aleph;
using namespace Aleph::CA;
 
namespace
{
  using Grid = Lattice<Dense_Cell_Storage<int, 2>, OpenBoundary>;
  using Engine = Synchronous_Engine<Grid, Game_Of_Life_Rule, Moore<2, 1>>;
  using Cell = std::pair<ca_index_t, ca_index_t>;
 
  std::set<Cell> to_set(std::initializer_list<Cell> cells)
  {
    return std::set<Cell>(cells.begin(), cells.end());
  }
 
  Grid make_grid(ca_size_t rows, ca_size_t cols,
                 std::initializer_list<Cell> alive)
  {
    Grid g({ rows, cols }, 0);
    for (const auto & c : alive)
      g.set({ c.first, c.second }, 1);
    return g;
  }
 
  Grid make_grid(ca_size_t rows, ca_size_t cols,
                 const std::vector<Cell> & alive)
  {
    Grid g({ rows, cols }, 0);
    for (const auto & c : alive)
      g.set({ c.first, c.second }, 1);
    return g;
  }
 
  std::set<Cell> alive_cells(const Grid & g)
  {
    std::set<Cell> out;
    const auto rows = static_cast<ca_index_t>(g.size(0));
    const auto cols = static_cast<ca_index_t>(g.size(1));
    for (ca_index_t i = 0; i < rows; ++i)
      for (ca_index_t j = 0; j < cols; ++j)
        if (g.at({ i, j }) != 0)
          out.insert({ i, j });
    return out;
  }
 
  Grid manual_life_step(const Grid & cur)
  {
    Grid nxt(cur.extents(), 0);
    auto rule = make_game_of_life_rule();
    Moore<2, 1> nh;
    std::array<int, Moore<2, 1>::size_v> buf { };
 
    const auto rows = static_cast<ca_index_t>(cur.size(0));
    const auto cols = static_cast<ca_index_t>(cur.size(1));
    for (ca_index_t i = 0; i < rows; ++i)
      for (ca_index_t j = 0; j < cols; ++j)
        {
          gather_neighbors(nh, cur, Coord_Vec<2>{ i, j },
                           std::span<int>(buf.data(), buf.size()));
          nxt.set({ i, j },
                  rule(cur.at({ i, j }),
                       Neighbor_View<int>(buf.data(), buf.size())));
        }
    return nxt;
  }
 
  Engine make_engine(Grid initial)
  {
    return Engine(std::move(initial), make_game_of_life_rule(), Moore<2, 1>{});
  }
 
  void expect_matches_reference_for_twenty_steps(Grid initial,
                                                 const char * name)
  {
    Grid ref = initial;
    auto engine = make_engine(std::move(initial));
    for (std::size_t t = 0; t < 20; ++t)
      {
        ASSERT_EQ(alive_cells(engine.frame()), alive_cells(ref))
          << name << " before step " << t;
        engine.step();
        ref = manual_life_step(ref);
      }
    EXPECT_EQ(alive_cells(engine.frame()), alive_cells(ref))
      << name << " after 20 steps";
    EXPECT_EQ(engine.steps_run(), 20u);
  }
 
  Grid make_pulsar()
  {
    Grid g({ 17, 17 }, 0);
    constexpr int offset = 2;
    const std::array<int, 4> sparse_rows = {{ 0, 5, 7, 12 }};
    const std::array<int, 6> dense_cols = {{ 2, 3, 4, 8, 9, 10 }};
    for (const int r : sparse_rows)
      for (const int c : dense_cols)
        g.set({ offset + r, offset + c }, 1);
 
    const std::array<int, 6> dense_rows = {{ 2, 3, 4, 8, 9, 10 }};
    const std::array<int, 4> sparse_cols = {{ 0, 5, 7, 12 }};
    for (const int r : dense_rows)
      for (const int c : sparse_cols)
        g.set({ offset + r, offset + c }, 1);
    return g;
  }
 
  std::vector<Cell> glider_cells()
  {
    return { { 1, 2 }, { 2, 3 }, { 3, 1 }, { 3, 2 }, { 3, 3 } };
  }
 
  std::set<Cell> shifted(const std::vector<Cell> & cells,
                         ca_index_t dr, ca_index_t dc)
  {
    std::set<Cell> out;
    for (const auto & c : cells)
      out.insert({ c.first + dr, c.second + dc });
    return out;
  }
}
 
TEST(CAEngineSync, MatchesManualReferenceForCanonicalPatterns)
{
  expect_matches_reference_for_twenty_steps(
    make_grid(5, 5, { { 2, 1 }, { 2, 2 }, { 2, 3 } }),
    "blinker");
  expect_matches_reference_for_twenty_steps(
    make_grid(6, 6, { { 2, 2 }, { 2, 3 }, { 2, 4 },
                      { 3, 1 }, { 3, 2 }, { 3, 3 } }),
    "toad");
  expect_matches_reference_for_twenty_steps(
    make_grid(6, 6, { { 1, 1 }, { 1, 2 }, { 2, 1 }, { 2, 2 },
                      { 3, 3 }, { 3, 4 }, { 4, 3 }, { 4, 4 } }),
    "beacon");
  expect_matches_reference_for_twenty_steps(
    make_grid(10, 10, glider_cells()),
    "glider");
  expect_matches_reference_for_twenty_steps(make_pulsar(), "pulsar");
}
 
TEST(CAEngineSync, OscillatorsFollowKnownPeriodsForTwentySteps)
{
  auto blinker = make_engine(
    make_grid(5, 5, { { 2, 1 }, { 2, 2 }, { 2, 3 } }));
  auto toad = make_engine(
    make_grid(6, 6, { { 2, 2 }, { 2, 3 }, { 2, 4 },
                      { 3, 1 }, { 3, 2 }, { 3, 3 } }));
  auto beacon = make_engine(
    make_grid(6, 6, { { 1, 1 }, { 1, 2 }, { 2, 1 }, { 2, 2 },
                      { 3, 3 }, { 3, 4 }, { 4, 3 }, { 4, 4 } }));
 
  const auto blinker0 = to_set({ { 2, 1 }, { 2, 2 }, { 2, 3 } });
  const auto blinker1 = to_set({ { 1, 2 }, { 2, 2 }, { 3, 2 } });
  const auto toad0 = to_set({ { 2, 2 }, { 2, 3 }, { 2, 4 },
                              { 3, 1 }, { 3, 2 }, { 3, 3 } });
  const auto toad1 = to_set({ { 1, 3 }, { 2, 1 }, { 2, 4 },
                              { 3, 1 }, { 3, 4 }, { 4, 2 } });
  const auto beacon0 = to_set({ { 1, 1 }, { 1, 2 }, { 2, 1 }, { 2, 2 },
                                { 3, 3 }, { 3, 4 }, { 4, 3 }, { 4, 4 } });
  const auto beacon1 = to_set({ { 1, 1 }, { 1, 2 }, { 2, 1 },
                                { 3, 4 }, { 4, 3 }, { 4, 4 } });
 
  for (std::size_t t = 0; t <= 20; ++t)
    {
      EXPECT_EQ(alive_cells(blinker.frame()), t % 2 == 0 ? blinker0 : blinker1)
        << "blinker t=" << t;
      EXPECT_EQ(alive_cells(toad.frame()), t % 2 == 0 ? toad0 : toad1)
        << "toad t=" << t;
      EXPECT_EQ(alive_cells(beacon.frame()), t % 2 == 0 ? beacon0 : beacon1)
        << "beacon t=" << t;
      if (t < 20)
        {
          blinker.step();
          toad.step();
          beacon.step();
        }
    }
}
 
TEST(CAEngineSync, GliderMovesOneCellDiagonallyEveryFourSteps)
{
  const auto cells = glider_cells();
  auto engine = make_engine(make_grid(10, 10, cells));
 
  for (std::size_t t = 0; t <= 20; ++t)
    {
      if (t % 4 == 0)
        {
          const auto d = static_cast<ca_index_t>(t / 4);
          EXPECT_EQ(alive_cells(engine.frame()), shifted(cells, d, d))
            << "glider t=" << t;
        }
      if (t < 20)
        engine.step();
    }
}
 
TEST(CAEngineSync, PulsarKeepsPeriodThree)
{
  const auto initial = alive_cells(make_pulsar());
  auto engine = make_engine(make_pulsar());
 
  for (std::size_t t = 1; t <= 20; ++t)
    {
      engine.step();
      if (t % 3 == 0)
        EXPECT_EQ(alive_cells(engine.frame()), initial) << "pulsar t=" << t;
    }
  EXPECT_EQ(engine.steps_run(), 20u);
}
 
TEST(CAEngineSync, HooksObservePreAndPostStepFrames)
{
  auto engine = make_engine(
    make_grid(5, 5, { { 2, 1 }, { 2, 2 }, { 2, 3 } }));
  std::vector<std::size_t> pre_steps;
  std::vector<std::size_t> post_steps;
  std::vector<std::size_t> pre_alive;
  std::vector<std::size_t> post_alive;
 
  engine.on_pre_step([&](std::size_t step, const Grid & frame)
    {
      pre_steps.push_back(step);
      pre_alive.push_back(alive_cells(frame).size());
    });
  engine.on_post_step([&](std::size_t step, const Grid & frame)
    {
      post_steps.push_back(step);
      post_alive.push_back(alive_cells(frame).size());
    });
 
  engine.run(2);
 
  EXPECT_EQ(pre_steps, (std::vector<std::size_t>{ 0, 1 }));
  EXPECT_EQ(post_steps, (std::vector<std::size_t>{ 1, 2 }));
  EXPECT_EQ(pre_alive, (std::vector<std::size_t>{ 3, 3 }));
  EXPECT_EQ(post_alive, (std::vector<std::size_t>{ 3, 3 }));
  EXPECT_EQ(engine.steps_run(), 2u);
}
 
TEST(CAEngineSync, TiledAndColumnMajorOrdersMatchRowMajor)
{
  using Tiled_Engine =
    Synchronous_Engine<Grid, Game_Of_Life_Rule, Moore<2, 1>, Tile<4, 3>>;
  using Column_Engine =
    Synchronous_Engine<Grid, Game_Of_Life_Rule, Moore<2, 1>, ColumnMajor>;
 
  Grid initial = make_pulsar();
  auto row_major = make_engine(initial);
  Tiled_Engine tiled(initial, make_game_of_life_rule(), Moore<2, 1>{});
  Column_Engine column(std::move(initial), make_game_of_life_rule(),
                       Moore<2, 1>{});
 
  for (std::size_t t = 0; t <= 20; ++t)
    {
      const auto expected = alive_cells(row_major.frame());
      EXPECT_EQ(alive_cells(tiled.frame()), expected) << "tiled t=" << t;
      EXPECT_EQ(alive_cells(column.frame()), expected) << "column t=" << t;
      if (t < 20)
        {
          row_major.step();
          tiled.step();
          column.step();
        }
    }
}
 
TEST(CAEngineUtils, WolframFactoryRunsSeededRule90Impulse)
{
  Lattice<Dense_Cell_Storage<int, 1>, OpenBoundary> row({ 7 }, 0);
  row.set({ 3 }, 1);
  auto engine = make_wolfram_engine(90, std::move(row));
 
  engine.step();
 
  EXPECT_EQ(engine.frame().at({ 0 }), 0);
  EXPECT_EQ(engine.frame().at({ 1 }), 0);
  EXPECT_EQ(engine.frame().at({ 2 }), 1);
  EXPECT_EQ(engine.frame().at({ 3 }), 0);
  EXPECT_EQ(engine.frame().at({ 4 }), 1);
  EXPECT_EQ(engine.frame().at({ 5 }), 0);
  EXPECT_EQ(engine.frame().at({ 6 }), 0);
  EXPECT_EQ(engine.steps_run(), 1u);
}