commit 817c22d36e7eaea29025ea4014b58eb648108687
parent 97eeac5b570b67e3fa6e327ec142ea0c5f135d49
Author: Dimitrije Dobrota <mail@dimitrijedobrota.com>
Date: Thu, 31 Aug 2023 19:19:19 +0200
Attack only move generation, general refactor
Diffstat:
11 files changed, 132 insertions(+), 125 deletions(-)
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -3,7 +3,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
project(
Stellar
- VERSION 0.0.28
+ VERSION 0.0.29
DESCRIPTION "Chess engine written in C"
HOMEPAGE_URL https://git.dimitrijedobrota.com/stellar.git
LANGUAGES C CXX
diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
@@ -13,7 +13,6 @@
#include "uci.hpp"
#include "utils.hpp"
-#define MAX_PLY 64
#define FULL_DEPTH 4
#define REDUCTION_LIMIT 3
#define REDUCTION_MOVE 2
@@ -37,7 +36,7 @@ struct Hashe {
class TTable {
public:
- static inline constexpr const uint16_t unknown = 32500;
+ static inline constexpr const int16_t unknown = 32500;
TTable() {}
TTable(U64 size) : table(size, {0}) {}
@@ -112,7 +111,7 @@ static RTable rtable;
static Move pv_table[MAX_PLY][MAX_PLY];
static Move killer[2][MAX_PLY];
static U32 history[12][64];
-static int pv_length[MAX_PLY];
+static uint8_t pv_length[MAX_PLY];
static bool follow_pv;
static U64 nodes;
static U32 ply;
@@ -157,14 +156,14 @@ std::vector<int> move_list_sort(MoveList &list, const Move best) {
return index;
}
-int evaluate(const Board &board) {
+int16_t evaluate(const Board &board) {
Color side = board.get_side();
Color sideOther = (side == Color::BLACK) ? Color::WHITE : Color::BLACK;
U64 occupancy = board.get_bitboard_color(side);
uint8_t square_i;
- int score = 0;
+ int16_t score = 0;
for (const piece::Type type : piece::TypeIter()) {
U64 bitboard = board.get_bitboard_piece(type);
bitboard_for_each_bit(square_i, bitboard) {
@@ -182,9 +181,9 @@ int evaluate(const Board &board) {
return score;
}
-int stats_move_make(Board ©, const Move move, int flag) {
+int stats_move_make(Board ©, const Move move) {
copy = board;
- if (!move.make(board, flag)) {
+ if (!move.make(board)) {
board = copy;
return 0;
}
@@ -221,7 +220,7 @@ void stats_pv_store(Move move) {
pv_length[ply] = pv_length[ply + 1];
}
-int quiescence(int16_t alpha, int16_t beta) {
+int16_t quiescence(int16_t alpha, int16_t beta) {
if ((nodes & 2047) == 0) {
uci::communicate(settings);
if (settings->stopped) return 0;
@@ -235,11 +234,10 @@ int quiescence(int16_t alpha, int16_t beta) {
if (score > alpha) alpha = score;
Board copy;
-
- MoveList list(board);
+ MoveList list(board, true);
for (int idx : move_list_sort(list, Move())) {
const Move move = list[idx];
- if (!stats_move_make(copy, list[idx], 1)) continue;
+ if (!stats_move_make(copy, move)) continue;
score = -quiescence(-beta, -alpha);
stats_move_unmake(copy, move);
@@ -255,7 +253,7 @@ int quiescence(int16_t alpha, int16_t beta) {
return alpha;
}
-int negamax(int16_t alpha, int16_t beta, uint8_t depth, bool null) {
+int16_t negamax(int16_t alpha, int16_t beta, uint8_t depth, bool null) {
int pv_node = (beta - alpha) > 1;
Hashe::Flag flag = Hashe::Flag::Alpha;
int futility = 0;
@@ -268,14 +266,18 @@ int negamax(int16_t alpha, int16_t beta, uint8_t depth, bool null) {
}
pv_length[ply] = ply;
- int score = ttable.read(board, ply, &bestMove, alpha, beta, depth);
- if (ply && score != TTable::unknown && !pv_node) return score;
-
// && fifty >= 100
if (ply && rtable.is_repetition(board.get_hash())) return 0;
+
+ int16_t score = ttable.read(board, ply, &bestMove, alpha, beta, depth);
+ if (ply && score != TTable::unknown && !pv_node) return score;
+
+ bool isCheck = board.is_check();
+ if (isCheck) depth++;
+
if (depth == 0) {
nodes++;
- int score = quiescence(alpha, beta);
+ int16_t score = quiescence(alpha, beta);
// ttable_write(board, ply, bestMove, score, depth, HasheFlag::Exact);
return score;
}
@@ -285,16 +287,13 @@ int negamax(int16_t alpha, int16_t beta, uint8_t depth, bool null) {
if (alpha >= beta) return alpha;
// if (ply > MAX_PLY - 1) return evaluate(board);
- int isCheck = board.is_check();
- if (isCheck) depth++;
-
if (!pv_node && !isCheck) {
static constexpr const U32 score_pawn = piece::score(piece::Type::PAWN);
- int staticEval = evaluate(board);
+ int16_t staticEval = evaluate(board);
// evaluation pruning
if (depth < 3 && abs(beta - 1) > -MATE_VALUE + 100) {
- int marginEval = score_pawn * depth;
+ int16_t marginEval = score_pawn * depth;
if (staticEval - marginEval >= beta) return staticEval - marginEval;
}
@@ -311,7 +310,7 @@ int negamax(int16_t alpha, int16_t beta, uint8_t depth, bool null) {
// razoring
score = staticEval + score_pawn;
- int scoreNew = quiescence(alpha, beta);
+ int16_t scoreNew = quiescence(alpha, beta);
if (score < beta && depth == 1) {
return (scoreNew > score) ? scoreNew : score;
@@ -324,7 +323,7 @@ int negamax(int16_t alpha, int16_t beta, uint8_t depth, bool null) {
}
// futility pruning condition
- static constexpr const int margin[] = {
+ static constexpr const int16_t margin[] = {
0,
piece::score(piece::Type::PAWN),
piece::score(piece::Type::KNIGHT),
@@ -333,13 +332,13 @@ int negamax(int16_t alpha, int16_t beta, uint8_t depth, bool null) {
if (depth < 4 && abs(alpha) < MATE_SCORE && staticEval + margin[depth] <= alpha) futility = 1;
}
- int legal_moves = 0;
- int searched = 0;
+ uint8_t legal_moves = 0;
+ uint8_t searched = 0;
MoveList list(board);
for (int idx : move_list_sort(list, bestMove)) {
const Move move = list[idx];
- if (!stats_move_make(copy, move, 0)) continue;
+ if (!stats_move_make(copy, move)) continue;
legal_moves++;
// futility pruning
@@ -408,7 +407,7 @@ int negamax(int16_t alpha, int16_t beta, uint8_t depth, bool null) {
return alpha;
}
-void search_position(const uci::Settings &settingsr) {
+Move search_position(const uci::Settings &settingsr) {
int16_t alpha = -SCORE_INFINITY, beta = SCORE_INFINITY;
settings = &settingsr;
@@ -421,7 +420,7 @@ void search_position(const uci::Settings &settingsr) {
for (int i = 0; i < settings->madeMoves.size(); i++) {
rtable.push_hash(board.get_hash());
settings->madeMoves[i].make(board);
- if (!settings->madeMoves[i].is_repetable()) rtable.push_null();
+ if (!settings->madeMoves[i].is_repetable()) rtable.clear();
}
ply = 0;
@@ -432,45 +431,27 @@ void search_position(const uci::Settings &settingsr) {
memset(pv_table, 0x00, sizeof(pv_table));
memset(pv_length, 0x00, sizeof(pv_length));
- for (uint8_t depth_crnt = 1; depth_crnt <= settings->depth;) {
+ for (uint8_t depth = 1; depth <= settings->depth; depth++) {
uci::communicate(settings);
if (settings->stopped) break;
follow_pv = 1;
- int score = negamax(alpha, beta, depth_crnt, true);
+ int16_t score = negamax(alpha, beta, depth, true);
if ((score <= alpha) || (score >= beta)) {
alpha = -SCORE_INFINITY;
beta = SCORE_INFINITY;
+ depth--;
continue;
}
alpha = score - WINDOW;
beta = score + WINDOW;
- if (pv_length[0]) {
- if (score > -MATE_VALUE && score < -MATE_SCORE) {
- std::cout << "info score mate " << -(score + MATE_VALUE) / 2 - 1;
- } else if (score > MATE_SCORE && score < MATE_VALUE) {
- std::cout << "info score mate " << (MATE_VALUE - score) / 2 + 1;
- } else {
- std::cout << "info score cp " << score;
- }
-
- std::cout << " depth " << (unsigned)depth_crnt;
- std::cout << " nodes " << nodes;
- std::cout << " pv ";
- for (int i = 0; i < pv_length[0]; i++) {
- uci::move_print(board, pv_table[0][i]);
- std::cout << " ";
- }
- std::cout << "\n";
- }
- depth_crnt++;
+ if (pv_length[0]) uci::pv_print(score, depth, nodes, pv_length, pv_table, board);
}
- std::cout << "bestmove ";
- uci::move_print(board, pv_table[0][0]);
- std::cout << "\n";
+ settings->board = board;
+ return pv_table[0][0];
}
} // namespace engine
diff --git a/src/engine/engine.hpp b/src/engine/engine.hpp
@@ -2,10 +2,13 @@
#define STELLAR_ENGINE_H
#include "engine/uci.hpp"
+#include "move.hpp"
#include "uci.hpp"
namespace engine {
-void search_position(const uci::Settings &setting);
+
+Move search_position(const uci::Settings &setting);
+
}
#endif
diff --git a/src/engine/score.hpp b/src/engine/score.hpp
@@ -1,6 +1,8 @@
#ifndef STELLAR_SCORE_H
#define STELLAR_SCORE_H
+#define MAX_PLY 64
+
#define SCORE_INFINITY 32000
#define MATE_VALUE 31000
#define MATE_SCORE 30000
diff --git a/src/engine/uci.cpp b/src/engine/uci.cpp
@@ -20,18 +20,31 @@ void move_print(const Board &board, Move move) {
if (move.is_promote()) std::cout << piece::get_code(move.promoted(), board.get_side());
}
-void communicate(const uci::Settings *settings) {
- if (!settings->infinite && uci::get_time_ms() > settings->stoptime) settings->stopped = true;
+void pv_print(int16_t score, uint8_t depth, uint64_t nodes, uint8_t pv_length[MAX_PLY],
+ Move pv_table[MAX_PLY][MAX_PLY], const Board &board) {
+ if (score > -MATE_VALUE && score < -MATE_SCORE) {
+ std::cout << "info score mate " << -(score + MATE_VALUE) / 2 - 1;
+ } else if (score > MATE_SCORE && score < MATE_VALUE) {
+ std::cout << "info score mate " << (MATE_VALUE - score) / 2 + 1;
+ } else {
+ std::cout << "info score cp " << score;
+ }
- /*
- if (std::cin.peek() == EOF || std::cin.peek() == '\n') {
- std::cin.clear();
+ std::cout << " depth " << (unsigned)depth;
+ std::cout << " nodes " << nodes;
+ std::cout << " pv ";
+ for (int i = 0; i < pv_length[0]; i++) {
+ uci::move_print(board, pv_table[0][i]);
+ std::cout << " ";
+ }
+ std::cout << "\n";
+}
+
+void communicate(const uci::Settings *settings) {
+ if (!settings->infinite && uci::get_time_ms() > settings->stoptime) {
+ settings->stopped = true;
return;
}
- std::string command;
- std::cin >> command;
- if (command == "stop" || command == "quit") settings->stopped = true;
- */
}
inline bool parse_move(const Board &board, Move &move, const std::string &move_string) {
@@ -148,8 +161,11 @@ void loop(void) {
if (!time) settings.infinite = true;
- // std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
- engine::search_position(settings);
+ const Move best = engine::search_position(settings);
+ std::cout << "bestmove ";
+ uci::move_print(settings.board, best);
+ std::cout << "\n";
+
settings.newgame = false;
}
}
diff --git a/src/engine/uci.hpp b/src/engine/uci.hpp
@@ -4,15 +4,17 @@
#include "board.hpp"
#include "move.hpp"
#include "movelist.hpp"
+#include "score.hpp"
#include "utils.hpp"
namespace uci {
struct Settings {
+ mutable Board board;
+
MoveList searchMoves;
MoveList madeMoves;
- Board board;
uint32_t starttime;
uint32_t stoptime;
uint16_t depth = 64;
@@ -28,6 +30,8 @@ struct Settings {
};
void loop(void);
+void pv_print(int16_t score, uint8_t depth, uint64_t nodes, uint8_t pv_length[MAX_PLY],
+ Move pv_table[MAX_PLY][MAX_PLY], const Board &board);
void move_print(const Board &board, Move move);
void communicate(const uci::Settings *settings);
uint32_t get_time_ms(void);
diff --git a/src/move/move.cpp b/src/move/move.cpp
@@ -22,7 +22,7 @@ void Move::piece_move(Board &board, piece::Type type, Color color, Square source
using piece::Type::PAWN;
using piece::Type::ROOK;
-bool Move::make(Board &board, bool attack_only) const {
+bool Move::make(Board &board) const {
static constexpr const int castling_rights[64] = {
// clang-format off
13, 15, 15, 15, 12, 15, 15, 14,
@@ -36,63 +36,58 @@ bool Move::make(Board &board, bool attack_only) const {
// clang-format on
};
- if (attack_only) {
- if (is_capture()) return make(board, false);
- return 0;
+ const Color color = board.get_side();
+ const Color colorOther = color == Color::BLACK ? Color::WHITE : Color::BLACK;
+ const Square source = this->source();
+ const Square target = this->target();
+
+ const Square ntarget =
+ static_cast<Square>(to_underlying(this->target()) + (color == Color::WHITE ? -8 : +8));
+
+ const piece::Type piece = board.get_square_piece_type(source);
+
+ if (!is_capture()) {
+ if (is_promote()) {
+ piece_remove(board, piece, color, source);
+ piece_set(board, promoted(), color, target);
+ } else {
+ piece_move(board, piece, color, source, target);
+ }
} else {
- const Color color = board.get_side();
- const Color colorOther = color == Color::BLACK ? Color::WHITE : Color::BLACK;
- const Square source = this->source();
- const Square target = this->target();
-
- const Square ntarget =
- static_cast<Square>(to_underlying(this->target()) + (color == Color::WHITE ? -8 : +8));
-
- const piece::Type piece = board.get_square_piece_type(source);
-
- if (!is_capture()) {
- if (is_promote()) {
- piece_remove(board, piece, color, source);
- piece_set(board, promoted(), color, target);
- } else {
- piece_move(board, piece, color, source, target);
- }
+ const piece::Type captured = board.get_square_piece_type(target);
+ if (is_enpassant()) {
+ piece_move(board, piece, color, source, target);
+ piece_remove(board, PAWN, colorOther, ntarget);
+ } else if (is_promote()) {
+ piece_remove(board, piece, color, source);
+ piece_remove(board, captured, colorOther, target);
+ piece_set(board, promoted(), color, target);
} else {
- const piece::Type captured = board.get_square_piece_type(target);
- if (is_enpassant()) {
- piece_move(board, piece, color, source, target);
- piece_remove(board, PAWN, colorOther, ntarget);
- } else if (is_promote()) {
- piece_remove(board, piece, color, source);
- piece_remove(board, captured, colorOther, target);
- piece_set(board, promoted(), color, target);
- } else {
- piece_remove(board, captured, colorOther, target);
- piece_move(board, piece, color, source, target);
- }
+ piece_remove(board, captured, colorOther, target);
+ piece_move(board, piece, color, source, target);
}
+ }
- board.set_enpassant(is_double() ? ntarget : Square::no_sq);
+ board.set_enpassant(is_double() ? ntarget : Square::no_sq);
- if (is_castle()) {
- if (color == Color::WHITE) {
- if (is_castle_king()) piece_move(board, ROOK, Color::WHITE, Square::h1, Square::f1);
- if (is_castle_queen()) piece_move(board, ROOK, Color::WHITE, Square::a1, Square::d1);
- } else {
- if (is_castle_king()) piece_move(board, ROOK, Color::BLACK, Square::h8, Square::f8);
- if (is_castle_queen()) piece_move(board, ROOK, Color::BLACK, Square::a8, Square::d8);
- }
+ if (is_castle()) {
+ if (color == Color::WHITE) {
+ if (is_castle_king()) piece_move(board, ROOK, Color::WHITE, Square::h1, Square::f1);
+ if (is_castle_queen()) piece_move(board, ROOK, Color::WHITE, Square::a1, Square::d1);
+ } else {
+ if (is_castle_king()) piece_move(board, ROOK, Color::BLACK, Square::h8, Square::f8);
+ if (is_castle_queen()) piece_move(board, ROOK, Color::BLACK, Square::a8, Square::d8);
}
+ }
- board.and_castle(castling_rights[to_underlying(this->source())] &
- castling_rights[to_underlying(this->target())]);
+ board.and_castle(castling_rights[to_underlying(this->source())] &
+ castling_rights[to_underlying(this->target())]);
- if (!board.is_check()) {
- board.switch_side();
- return 1;
- }
- return 0;
+ if (!board.is_check()) {
+ board.switch_side();
+ return 1;
}
+ return 0;
}
std::ostream &operator<<(std::ostream &os, Move move) {
diff --git a/src/move/move.hpp b/src/move/move.hpp
@@ -53,7 +53,7 @@ struct Move {
const piece::Type promoted(void) const { return static_cast<piece::Type>((flags_i & 0x3) + 1); }
- bool make(Board &board, bool attack_only = false) const;
+ bool make(Board &board) const;
friend std::ostream &operator<<(std::ostream &os, Move move);
diff --git a/src/move/movelist.cpp b/src/move/movelist.cpp
@@ -12,7 +12,7 @@
using piece::Type::PAWN;
-void MoveList::generate(const Board &board) {
+void MoveList::generate(const Board &board, bool attacks_only) {
uint8_t src_i, tgt_i;
Color color = board.get_side();
@@ -25,7 +25,7 @@ void MoveList::generate(const Board &board) {
bitboard_for_each_bit(src_i, bitboard) {
const Square src = static_cast<Square>(src_i);
const Square tgt = static_cast<Square>(tgt_i = src_i + add);
- if (!board.is_square_occupied(tgt)) {
+ if (!attacks_only && !board.is_square_occupied(tgt)) {
if (pawn_canPromote(color, src)) {
list.push_back({src, tgt, Move::PKNIGHT});
list.push_back({src, tgt, Move::PBISHOP});
@@ -70,11 +70,18 @@ void MoveList::generate(const Board &board) {
U64 attack = board.get_bitboard_piece_moves(type, color, src);
bitboard_for_each_bit(tgt_i, attack) {
const Square tgt = static_cast<Square>(tgt_i);
- list.push_back({src, tgt, board.is_square_occupied(tgt) ? Move::CAPTURE : Move::QUIET});
+ if (board.is_square_occupied(tgt)) {
+ list.push_back({src, tgt, Move::CAPTURE});
+ } else {
+ if (attacks_only) continue;
+ list.push_back({src, tgt, Move::QUIET});
+ }
}
}
}
+ if (attacks_only) return;
+
// Castling
if (color == Color::WHITE) {
if (!board.is_square_attacked(Square::e1, Color::BLACK)) {
diff --git a/src/move/movelist.hpp b/src/move/movelist.hpp
@@ -12,13 +12,12 @@
class MoveList {
private:
using list_t = std::vector<Move>;
- using index_t = std::vector<int>;
public:
MoveList() : list(){};
- MoveList(const Board &board) : list() {
+ MoveList(const Board &board, bool attacks_only = false) : list() {
list.reserve(256);
- generate(board);
+ generate(board, attacks_only);
}
void clear() { list.clear(); }
@@ -30,7 +29,7 @@ class MoveList {
friend std::ostream &operator<<(std::ostream &os, const MoveList &list);
private:
- void generate(const Board &board);
+ void generate(const Board &board, bool attacks_only);
list_t list;
};
diff --git a/src/perft/perft.cpp b/src/perft/perft.cpp
@@ -18,7 +18,7 @@ class Perft {
Perft(semaphore_t &sem) : sem(sem) {}
void operator()(const Board &board_start, Move move, int depth) {
Board board = board_start;
- if (!move.make(board, 0)) return;
+ if (!move.make(board)) return;
sem.acquire();
// debug(board_start, move, board);
@@ -63,7 +63,7 @@ class Perft {
const MoveList list(board);
for (int i = 0; i < list.size(); i++) {
Board copy = board;
- if (!list[i].make(copy, 0)) continue;
+ if (!list[i].make(copy)) continue;
// debug(board, list[i], copy);
if (depth != 1)
test(copy, depth - 1);
