Skip to content

Commit

Permalink
remove ply from absearch #100
Browse files Browse the repository at this point in the history 
remove ply from absearch

Bench: 6192504
  • Loading branch information
@Disservin
Disservin authored Jul 6, 2022
2 parents e97acaa + 119886e commit 220ecd4
Show file tree
Hide file tree
Showing 2 changed files with 24 additions and 24 deletions.
46 changes: 23 additions & 23 deletions src/search.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,26 +57,26 @@ Score Search::qsearch(int depth, Score alpha, Score beta, int ply, ThreadData *t
return bestValue;
}

Score Search::absearch(int depth, Score alpha, Score beta, int ply, Stack *ss, ThreadData *td) {
Score Search::absearch(int depth, Score alpha, Score beta, Stack *ss, ThreadData *td) {
if (exit_early(td->nodes, td->id)) return 0;
if (ply > MAX_PLY - 1) return evaluation(td->board);
if (ss->ply > MAX_PLY - 1) return evaluation(td->board);

Score best = -VALUE_INFINITE;
td->pv_length[ply] = ply;
td->pv_length[ss->ply] = ss->ply;
Score oldAlpha = alpha;
bool RootNode = ply == 0;
bool RootNode = ss->ply == 0;
Color color = td->board.sideToMove;

if (ply >= 1 && td->board.isRepetition() && !((ss-1)->currentmove == nullmove)) return 0;
if (ss->ply >= 1 && td->board.isRepetition() && (ss-1)->currentmove != nullmove) return 0;
if (!RootNode) {
if (td->board.halfMoveClock >= 100) return 0;
int all = popcount(td->board.All());
if (all == 2) return 0;
if (all == 3 && (td->board.Bitboards[WhiteKnight] || td->board.Bitboards[BlackKnight])) return 0;
if (all == 3 && (td->board.Bitboards[WhiteBishop] || td->board.Bitboards[BlackBishop])) return 0;

alpha = std::max(alpha, (int16_t)(-VALUE_MATE + ply));
beta = std::min(beta, (int16_t)(VALUE_MATE - ply - 1));
alpha = std::max(alpha, (int16_t)(-VALUE_MATE + ss->ply));
beta = std::min(beta, (int16_t)(VALUE_MATE - ss->ply - 1));
if (alpha >= beta) return alpha;
}

Expand All @@ -87,10 +87,10 @@ Score Search::absearch(int depth, Score alpha, Score beta, int ply, Stack *ss, T
if (inCheck) depth++;

// Enter qsearch
if (depth <= 0) return qsearch(15, alpha, beta, ply, td);
if (depth <= 0) return qsearch(15, alpha, beta, ss->ply, td);

// Selective depth (heighest depth we have ever reached)
if (ply > td->seldepth) td->seldepth = ply;
if (ss->ply > td->seldepth) td->seldepth = ss->ply;

Score staticEval;

Expand Down Expand Up @@ -123,7 +123,7 @@ Score Search::absearch(int depth, Score alpha, Score beta, int ply, Stack *ss, T
&& depth < 2
&& staticEval + 640 < alpha
&& !inCheck)
return qsearch(15, alpha, beta, ply, td);
return qsearch(15, alpha, beta, ss->ply, td);

// Reverse futility pruning
if (std::abs(beta) < VALUE_MATE_IN_PLY && !inCheck && !PvNode) {
Expand All @@ -139,7 +139,7 @@ Score Search::absearch(int depth, Score alpha, Score beta, int ply, Stack *ss, T
int r = 3 + depth / 5;
td->board.makeNullMove();
(ss)->currentmove = nullmove;
Score score = -absearch(depth - r, -beta, -beta + 1, ply + 1, ss+1, td);
Score score = -absearch(depth - r, -beta, -beta + 1, ss+1, td);
td->board.unmakeNullMove();
if (score >= beta) return beta;
}
Expand All @@ -151,12 +151,12 @@ Score Search::absearch(int depth, Score alpha, Score beta, int ply, Stack *ss, T

// if the move list is empty, we are in checkmate or stalemate
if (ml.size == 0) {
return inCheck ? -VALUE_MATE + ply : 0;
return inCheck ? -VALUE_MATE + ss->ply : 0;
}

// assign a value to each move
for (int i = 0; i < ml.size; i++) {
ml.list[i].value = score_move(ml.list[i], ply, ttHit, td);
ml.list[i].value = score_move(ml.list[i], ss->ply, ttHit, td);
}

if (RootNode && td->id == 0) rootSize = ml.size;
Expand Down Expand Up @@ -222,20 +222,20 @@ Score Search::absearch(int depth, Score alpha, Score beta, int ply, Stack *ss, T
if (madeMoves > 15 && !capture)
rdepth--;

score = -absearch(rdepth, -alpha - 1, -alpha, ply + 1, ss+1, td);
score = -absearch(rdepth, -alpha - 1, -alpha, ss+1, td);
doFullSearch = score > alpha;
}
else
doFullSearch = !PvNode || madeMoves > 1;

// do a full research if lmr failed or lmr was skipped
if (doFullSearch) {
score = -absearch(depth - 1, -alpha - 1, -alpha, ply + 1, ss+1, td);
score = -absearch(depth - 1, -alpha - 1, -alpha, ss+1, td);
}

// PVS search
if (PvNode && ((score > alpha && score < beta) || madeMoves == 1)) {
score = -absearch(depth - 1, -beta, -alpha, ply + 1, ss+1, td);
score = -absearch(depth - 1, -beta, -alpha, ss+1, td);
}

td->board.unmakeMove(move);
Expand All @@ -246,20 +246,20 @@ Score Search::absearch(int depth, Score alpha, Score beta, int ply, Stack *ss, T
bestMove = move;

// update the PV
td->pv_table[ply][ply] = move;
for (int next_ply = ply + 1; next_ply < td->pv_length[ply + 1]; next_ply++) {
td->pv_table[ply][next_ply] = td->pv_table[ply + 1][next_ply];
td->pv_table[ss->ply][ss->ply] = move;
for (int next_ply = ss->ply + 1; next_ply < td->pv_length[ss->ply + 1]; next_ply++) {
td->pv_table[ss->ply][next_ply] = td->pv_table[ss->ply + 1][next_ply];
}
td->pv_length[ply] = td->pv_length[ply + 1];
td->pv_length[ss->ply] = td->pv_length[ss->ply + 1];

if (score > alpha) {
alpha = score;

if (score >= beta) {
// update Killer Moves
if (!capture) {
td->killerMoves[1][ply] = td->killerMoves[0][ply];
td->killerMoves[0][ply] = move;
td->killerMoves[1][ss->ply] = td->killerMoves[0][ss->ply];
td->killerMoves[0][ss->ply] = move;
}
break;
}
Expand Down Expand Up @@ -292,7 +292,7 @@ Score Search::aspiration_search(int depth, Score prev_eval, Stack *ss, ThreadDat
if (stopped) return 0;
if (alpha < -3500) alpha = -VALUE_INFINITE;
if (beta > 3500) beta = VALUE_INFINITE;
result = absearch(depth, alpha, beta, 0, ss, td);
result = absearch(depth, alpha, beta, ss, td);
if (result <= alpha) {
research++;
alpha = std::max(alpha - research * research * delta, -((int)VALUE_INFINITE));
Expand Down
2 changes: 1 addition & 1 deletion src/search.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@ class Search {

// main search functions
Score qsearch(int depth, Score alpha, Score beta, int ply, ThreadData *td);
Score absearch(int depth, Score alpha, Score beta, int ply, Stack *ss, ThreadData *td);
Score absearch(int depth, Score alpha, Score beta, Stack *ss, ThreadData *td);
Score aspiration_search(int depth, Score prev_eval, Stack *ss, ThreadData *td);
void iterative_deepening(int search_depth, uint64_t maxN, Time time, int threadId);
void start_thinking(Board board, int workers, int search_depth, uint64_t maxN, Time time);
Expand Down

0 comments on commit 220ecd4

Please sign in to comment.