ladybird/Userland/Services/ChessEngine/MCTSTree.h
Daniel Bertalan 6f6b1b3ea1 ChessEngine: Don't call non-constexpr sqrt in a constexpr intiializer
GCC likely has a builtin intrinsic that evaluates the operation at
compile-time, even if the `LibM` is not declared as constexpr. Clang,
however, does not like it, and it failed to compile this code.
2021-07-08 10:11:00 +02:00

51 lines
1.3 KiB
C++

/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Function.h>
#include <AK/NonnullOwnPtrVector.h>
#include <AK/OwnPtr.h>
#include <LibChess/Chess.h>
#include <math.h>
class MCTSTree {
public:
enum EvalMethod {
Simulation,
Heuristic,
};
MCTSTree(const Chess::Board& board, MCTSTree* parent = nullptr);
MCTSTree& select_leaf();
MCTSTree& expand();
int simulate_game() const;
int heuristic() const;
void apply_result(int game_score);
void do_round();
Chess::Move best_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 };
// FIXME: Optimize simulations enough for use.
static constexpr EvalMethod s_eval_method { EvalMethod::Heuristic };
NonnullOwnPtrVector<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 };
};