stellar

Mate Detection

5 files changed, 63 insertions(+), 42 deletions(-)

diff --git a/ CMakeLists.txt b/ CMakeLists.txt

@@ -3,7 +3,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON) project( Stellar

VERSION 0.0.14

VERSION 0.0.15

DESCRIPTION "Chess engine written in C" HOMEPAGE_URL https://git.dimitrijedobrota.com/stellar.git LANGUAGES C

diff --git a/ src/board/board.c b/ src/board/board.c

@@ -203,7 +203,7 @@ void board_print(const Board *self) { if (!file) printf(" %d ", 8 - rank);

printf("%s", (piece) ? piece_unicode(piece) : ". ");

printf("%c ", (piece) ? piece_asci(piece) : '.');

} printf("\n"); }

diff --git a/ src/engine/engine.c b/ src/engine/engine.c

@@ -19,6 +19,9 @@ #define REDUCTION_MOVE 2 #define INFINITY 50000

#define MATE_VALUE 49000

#define MATE_SCORE 48000

#define WINDOW 50 typedef struct Stats Stats;

@@ -112,9 +115,10 @@ int evaluate(const Board *board) { } int quiescence(Stats *stats, const Board *board, int alpha, int beta) {

int eval = evaluate(board);

stats->nodes++;

int eval = evaluate(board);

if (stats->ply > MAX_PLY - 1) return eval;

if (eval >= beta) return beta; if (eval > alpha) alpha = eval;

@@ -126,27 +130,32 @@ int quiescence(Stats *stats, const Board *board, int alpha, int beta) { for (int i = 0; i < move_list_size(&moves); i++) { board_copy(board, &copy);

if (move_make(move_list_move(&moves, i), &copy, 1) == 0) continue;

Move move = move_list_move(&moves, i);

if (move_make(move, &copy, 1) == 0) continue;

stats->ply++; int score = -quiescence(stats, &copy, -beta, -alpha); stats->ply--;

if (score >= beta) return beta;

if (score > alpha) alpha = score;

if (score > alpha) {

alpha = score;

if (score >= beta) return beta;

}

} return alpha; } int negamax(Stats *stats, const Board *board, int alpha, int beta, int depth) {

int ply = stats->ply;

stats->pv_length[ply] = ply;

stats->pv_length[stats->ply] = stats->ply;

stats->nodes++;

if (depth == 0) return quiescence(stats, board, alpha, beta);

if (ply > MAX_PLY - 1) return evaluate(board);

if (stats->ply > MAX_PLY - 1) return evaluate(board);

stats->nodes++;

// if (alpha < -MATE_VALUE) alpha = -MATE_VALUE;

// if (beta > MATE_VALUE - 1) beta = MATE_VALUE - 1;

// if (alpha >= beta) return alpha;

int isCheck = board_isCheck(board); if (isCheck) depth++;

@@ -158,7 +167,7 @@ int negamax(Stats *stats, const Board *board, int alpha, int beta, int depth) { board_side_switch(&copy); board_enpassant_set(&copy, no_sq);

int score = -negamax(stats, &copy, -beta, -beta + 2,

int score = -negamax(stats, &copy, -beta, -beta + 1,

depth - 1 - REDUCTION_MOVE); if (score >= beta) return beta;

@@ -170,16 +179,16 @@ int negamax(Stats *stats, const Board *board, int alpha, int beta, int depth) { if (stats->follow_pv) enable_pv_scoring(stats, &list); move_list_sort(stats, &list);

int legal_moves = 0; int searched = 0; for (int i = 0; i < move_list_size(&list); i++) { Move move = move_list_move(&list, i); board_copy(board, &copy);

if (move_make(move, &copy, 0) == 0) {

continue;

}

int makeCheck = board_isCheck(&copy);

if (move_make(move, &copy, 0) == 0) continue;

legal_moves++;

stats->ply++; int score;

@@ -188,7 +197,7 @@ int negamax(Stats *stats, const Board *board, int alpha, int beta, int depth) { } else { // Late Move Reduction if (searched >= FULL_DEPTH && depth >= REDUCTION_LIMIT &&

!isCheck && !makeCheck && !move_capture(move) &&

!isCheck && !board_isCheck(&copy) && !move_capture(move) &&

!move_promote(move)) { score = -negamax(stats, &copy, -alpha - 1, -alpha, depth - 2); } else

@@ -205,33 +214,35 @@ int negamax(Stats *stats, const Board *board, int alpha, int beta, int depth) { } stats->ply--;

legal_moves++;

searched++;

if (score >= beta) {

if (!move_capture(move)) {

stats->killer_moves[1][ply] = stats->killer_moves[0][ply];

stats->killer_moves[0][ply] = move;

}

return beta;

}

if (score > alpha) { if (!move_capture(move)) stats->history_moves[piece_index(move_piece(move))] [move_target(move)] += depth;

alpha = score;

stats->pv_table[ply][ply] = move;

for (int i = stats->ply + 1; i < stats->pv_length[ply + 1]; i++)

stats->pv_table[ply][i] = stats->pv_table[ply + 1][i];

stats->pv_length[ply] = stats->pv_length[ply + 1];

stats->pv_table[stats->ply][stats->ply] = move;

for (int i = stats->ply + 1; i < stats->pv_length[stats->ply + 1];

i++)

stats->pv_table[stats->ply][i] =

stats->pv_table[stats->ply + 1][i];

stats->pv_length[stats->ply] = stats->pv_length[stats->ply + 1];

if (score >= beta) {

if (!move_capture(move)) {

stats->killer_moves[1][stats->ply] =

stats->killer_moves[0][stats->ply];

stats->killer_moves[0][stats->ply] = move;

}

return beta;

}

} }

if (legal_moves == 0) {

if (isCheck)

return -49000 + stats->ply;

else

if (isCheck) {

return -MATE_VALUE + stats->ply;

} else

return 0; }

@@ -241,7 +252,7 @@ int negamax(Stats *stats, const Board *board, int alpha, int beta, int depth) { void move_print_UCI(Move move) { printf("%s%s", square_to_coordinates[move_source(move)], square_to_coordinates[move_target(move)]);

if (move_promote(move)) printf(" %c", piece_asci(move_piece_promote(move)));

if (move_promote(move)) printf("%c", piece_asci(move_piece_promote(move)));

} void search_position(const Board *board, int depth) {

@@ -259,8 +270,16 @@ void search_position(const Board *board, int depth) { alpha = score - 50; beta = score + 50;

printf("info score cp %d depth %d nodes %ld pv ", score, crnt,

stats.nodes);

if (score > -MATE_VALUE && score < -MATE_SCORE) {

printf("info score mate %d depth %d nodes %ld pv ",

(MATE_VALUE - score) / 2 + 1, crnt, stats.nodes);

} else if (score > MATE_SCORE && score < MATE_VALUE) {

printf("info score mate %d depth %d nodes %ld pv ",

(MATE_VALUE - score) / 2 + 1, crnt, stats.nodes);

} else {

printf("info score cp %d depth %d nodes %ld pv ", score, crnt,

stats.nodes);

}

for (int i = 0; i < stats.pv_length[0]; i++) { move_print_UCI(stats.pv_table[0][i]);

@@ -414,7 +433,7 @@ Board *Instruction_parse(Instruction *self, Board *board) { token = Instruction_token_next(self); depth = atoi(token); } else {

printf("Unknown argument %s after go\n", token);

// printf("Unknown argument %s after go\n", token);

} } search_position(board, depth);

diff --git a/ src/moves/moves.c b/ src/moves/moves.c

@@ -25,12 +25,12 @@ Move move_encode(Square src, Square tgt, Piece piece, Piece capture, } void move_print(Move move) {

printf("%5s %5s %2s %2s %2s %4d %4d %4d %4d %4d\n",

printf("%5s %5s %2c %2c %2c %4d %4d %4d %4d %4d\n",

square_to_coordinates[move_source(move)], square_to_coordinates[move_target(move)],

piece_unicode(move_piece(move)),

move_capture(move) ? piece_unicode(move_piece_capture(move)) : "X ",

move_promote(move) ? piece_unicode(move_piece_promote(move)) : "X ",

piece_asci(move_piece(move)),

move_capture(move) ? piece_asci(move_piece_capture(move)) : '.',

move_promote(move) ? piece_asci(move_piece_promote(move)) : '.',

move_double(move) ? 1 : 0, move_enpassant(move) ? 1 : 0, move_castle(move) ? 1 : 0, move_capture(move) ? 1 : 0, move_promote(move) ? 1 : 0);

diff --git a/ src/score/score.c b/ src/score/score.c

@@ -114,4 +114,6 @@ int Score_position(ePiece piece, eColor color, Square square) { return Scores[piece].position[square]; }

int Score_capture(ePiece src, ePiece tgt) { return Scores[src].capture[tgt]; }

int Score_capture(ePiece src, ePiece tgt) {

return Scores[src].capture[tgt] + 10000;

}