ladybird/Userland/Services/ChessEngine/MCTSTree.h
2023-03-06 23:46:35 +01:00

57 lines
1.5 KiB
C++

/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Function.h>
#include <AK/OwnPtr.h>
#include <LibChess/Chess.h>
#include <math.h>
class MCTSTree {
public:
enum EvalMethod {
Simulation,
Heuristic,
};
MCTSTree(Chess::Board const& board, MCTSTree* parent = nullptr);
MCTSTree(MCTSTree&&);
MCTSTree& select_leaf();
MCTSTree& expand();
int simulate_game() const;
int heuristic() const;
void apply_result(int game_score);
void do_round();
Optional<MCTSTree&> child_with_move(Chess::Move);
MCTSTree& best_node();
Chess::Move last_move() const;
double expected_value() const;
double uct(Chess::Color color) const;
bool expanded() const;
private:
// While static parameters are less configurable, they don't take up any
// memory in the tree, which I believe to be a worthy tradeoff.
static constexpr double s_exploration_parameter { M_SQRT2 };
static constexpr int s_number_of_visit_parameter { 1 };
// FIXME: Optimize simulations enough for use.
static constexpr EvalMethod s_eval_method { EvalMethod::Heuristic };
Vector<NonnullOwnPtr<MCTSTree>> m_children;
MCTSTree* m_parent { nullptr };
int m_white_points { 0 };
int m_simulations { 0 };
OwnPtr<Chess::Board> m_board;
Optional<Chess::Move> m_last_move;
Chess::Color m_turn : 2;
bool m_moves_generated : 1 { false };
};