X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=cf7e411d8504e2c2cba05869d91aaccdafcd137a;hp=59b1b1f19a84f19dccb8c58b288d53c6944ace9c;hb=6aa9308f08bc76b0e3615dde65de7782a6761fa3;hpb=76971d8acba4af1896cf94e1278f69ae2084d45d;ds=sidebyside diff --git a/src/search.cpp b/src/search.cpp index 59b1b1f1..cf7e411d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -65,14 +65,14 @@ namespace { // Razoring and futility margin based on depth const int razor_margin[4] = { 483, 570, 603, 554 }; - Value futility_margin(Depth d) { return Value(200 * d); } + Value futility_margin(Depth d) { return Value(150 * d / ONE_PLY); } // Futility and reductions lookup tables, initialized at startup - int FutilityMoveCounts[2][16]; // [improving][depth] - Depth Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber] + int FutilityMoveCounts[2][16]; // [improving][depth] + int Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber] template Depth reduction(bool i, Depth d, int mn) { - return Reductions[PvNode][i][std::min(d, 63 * ONE_PLY)][std::min(mn, 63)]; + return Reductions[PvNode][i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] * ONE_PLY; } // Skill structure is used to implement strength limit @@ -113,8 +113,8 @@ namespace { std::copy(newPv.begin(), newPv.begin() + 3, pv); StateInfo st[2]; - pos.do_move(newPv[0], st[0], pos.gives_check(newPv[0], CheckInfo(pos))); - pos.do_move(newPv[1], st[1], pos.gives_check(newPv[1], CheckInfo(pos))); + pos.do_move(newPv[0], st[0], pos.gives_check(newPv[0])); + pos.do_move(newPv[1], st[1], pos.gives_check(newPv[1])); expectedPosKey = pos.key(); pos.undo_move(newPv[1]); pos.undo_move(newPv[0]); @@ -168,7 +168,8 @@ namespace { Value value_to_tt(Value v, int ply); Value value_from_tt(Value v, int ply); void update_pv(Move* pv, Move move, Move* childPv); - void update_stats(const Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt); + void update_cm_stats(Stack* ss, Piece pc, Square s, Value bonus); + void update_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, Value bonus); void check_time(); } // namespace @@ -186,12 +187,12 @@ void Search::init() { if (r < 0.80) continue; - Reductions[NonPV][imp][d][mc] = int(std::round(r)) * ONE_PLY; - Reductions[PV][imp][d][mc] = std::max(Reductions[NonPV][imp][d][mc] - ONE_PLY, DEPTH_ZERO); + Reductions[NonPV][imp][d][mc] = int(std::round(r)); + Reductions[PV][imp][d][mc] = std::max(Reductions[NonPV][imp][d][mc] - 1, 0); // Increase reduction for non-PV nodes when eval is not improving - if (!imp && Reductions[NonPV][imp][d][mc] >= 2 * ONE_PLY) - Reductions[NonPV][imp][d][mc] += ONE_PLY; + if (!imp && Reductions[NonPV][imp][d][mc] >= 2) + Reductions[NonPV][imp][d][mc]++; } for (int d = 0; d < 16; ++d) @@ -213,6 +214,7 @@ void Search::clear() { { th->history.clear(); th->counterMoves.clear(); + th->fromTo.clear(); } Threads.main()->previousScore = VALUE_INFINITE; @@ -226,7 +228,6 @@ uint64_t Search::perft(Position& pos, Depth depth) { StateInfo st; uint64_t cnt, nodes = 0; - CheckInfo ci(pos); const bool leaf = (depth == 2 * ONE_PLY); for (const auto& m : MoveList(pos)) @@ -235,7 +236,7 @@ uint64_t Search::perft(Position& pos, Depth depth) { cnt = 1, nodes++; else { - pos.do_move(m, st, pos.gives_check(m, ci)); + pos.do_move(m, st, pos.gives_check(m)); cnt = leaf ? MoveList(pos).size() : perft(pos, depth - ONE_PLY); nodes += cnt; pos.undo_move(m); @@ -366,15 +367,17 @@ void Thread::search() { multiPV = std::min(multiPV, rootMoves.size()); - // Iterative deepening loop until requested to stop or the target depth is reached. - while (++rootDepth < DEPTH_MAX && !Signals.stop && (!Limits.depth || Threads.main()->rootDepth <= Limits.depth)) + // Iterative deepening loop until requested to stop or the target depth is reached + while ( (rootDepth += ONE_PLY) < DEPTH_MAX + && !Signals.stop + && (!Limits.depth || Threads.main()->rootDepth / ONE_PLY <= Limits.depth)) { // Set up the new depths for the helper threads skipping on average every // 2nd ply (using a half-density matrix). if (!mainThread) { const Row& row = HalfDensity[(idx - 1) % HalfDensitySize]; - if (row[(rootDepth + rootPos.game_ply()) % row.size()]) + if (row[(rootDepth / ONE_PLY + rootPos.game_ply()) % row.size()]) continue; } @@ -550,6 +553,7 @@ namespace { assert(PvNode || (alpha == beta - 1)); assert(DEPTH_ZERO < depth && depth < DEPTH_MAX); assert(!(PvNode && cutNode)); + assert(depth / ONE_PLY * ONE_PLY == depth); Move pv[MAX_PLY+1], quietsSearched[64]; StateInfo st; @@ -635,9 +639,24 @@ namespace { ss->currentMove = ttMove; // Can be MOVE_NONE // If ttMove is quiet, update killers, history, counter move on TT hit - if (ttValue >= beta && ttMove && !pos.capture_or_promotion(ttMove)) - update_stats(pos, ss, ttMove, depth, nullptr, 0); + if (ttValue >= beta && ttMove) + { + int d = depth / ONE_PLY; + + if (!pos.capture_or_promotion(ttMove)) + { + Value bonus = Value(d * d + 2 * d - 2); + update_stats(pos, ss, ttMove, nullptr, 0, bonus); + } + // Extra penalty for a quiet TT move in previous ply when it gets refuted + if ((ss-1)->moveCount == 1 && !pos.captured_piece_type()) + { + Value penalty = Value(d * d + 4 * d + 1); + Square prevSq = to_sq((ss-1)->currentMove); + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -penalty); + } + } return ttValue; } @@ -706,14 +725,14 @@ namespace { // Step 6. Razoring (skipped when in check) if ( !PvNode && depth < 4 * ONE_PLY - && eval + razor_margin[depth] <= alpha + && eval + razor_margin[depth / ONE_PLY] <= alpha && ttMove == MOVE_NONE) { if ( depth <= ONE_PLY && eval + razor_margin[3 * ONE_PLY] <= alpha) return qsearch(pos, ss, alpha, beta, DEPTH_ZERO); - Value ralpha = alpha - razor_margin[depth]; + Value ralpha = alpha - razor_margin[depth / ONE_PLY]; Value v = qsearch(pos, ss, ralpha, ralpha+1, DEPTH_ZERO); if (v <= ralpha) return v; @@ -729,7 +748,6 @@ namespace { // Step 8. Null move search with verification search (is omitted in PV nodes) if ( !PvNode - && depth >= 2 * ONE_PLY && eval >= beta && (ss->staticEval >= beta - 35 * (depth / ONE_PLY - 6) || depth >= 13 * ONE_PLY) && pos.non_pawn_material(pos.side_to_move())) @@ -740,7 +758,7 @@ namespace { assert(eval - beta >= 0); // Null move dynamic reduction based on depth and value - Depth R = ((823 + 67 * depth) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY; + Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY; pos.do_null_move(st); (ss+1)->skipEarlyPruning = true; @@ -770,9 +788,8 @@ namespace { } // Step 9. ProbCut (skipped when in check) - // If we have a very good capture (i.e. SEE > seeValues[captured_piece_type]) - // and a reduced search returns a value much above beta, we can (almost) - // safely prune the previous move. + // If we have a good enough capture and a reduced search returns a value + // much above beta, we can (almost) safely prune the previous move. if ( !PvNode && depth >= 5 * ONE_PLY && abs(beta) < VALUE_MATE_IN_MAX_PLY) @@ -784,15 +801,14 @@ namespace { assert((ss-1)->currentMove != MOVE_NONE); assert((ss-1)->currentMove != MOVE_NULL); - MovePicker mp(pos, ttMove, PieceValue[MG][pos.captured_piece_type()]); - CheckInfo ci(pos); + MovePicker mp(pos, ttMove, rbeta - ss->staticEval); while ((move = mp.next_move()) != MOVE_NONE) - if (pos.legal(move, ci.pinned)) + if (pos.legal(move)) { ss->currentMove = move; ss->counterMoves = &CounterMoveHistory[pos.moved_piece(move)][to_sq(move)]; - pos.do_move(move, st, pos.gives_check(move, ci)); + pos.do_move(move, st, pos.gives_check(move)); value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode); pos.undo_move(move); if (value >= rbeta) @@ -801,11 +817,11 @@ namespace { } // Step 10. Internal iterative deepening (skipped when in check) - if ( depth >= (PvNode ? 5 * ONE_PLY : 8 * ONE_PLY) + if ( depth >= 6 * ONE_PLY && !ttMove && (PvNode || ss->staticEval + 256 >= beta)) { - Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4); + Depth d = (3 * depth / (4 * ONE_PLY) - 2) * ONE_PLY; ss->skipEarlyPruning = true; search(pos, ss, alpha, beta, d, cutNode); ss->skipEarlyPruning = false; @@ -821,7 +837,6 @@ moves_loop: // When in check search starts from here const CounterMoveStats* fmh2 = (ss-4)->counterMoves; MovePicker mp(pos, ttMove, depth, ss); - CheckInfo ci(pos); value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc improving = ss->staticEval >= (ss-2)->staticEval /* || ss->staticEval == VALUE_NONE Already implicit in the previous condition */ @@ -866,12 +881,12 @@ moves_loop: // When in check search starts from here captureOrPromotion = pos.capture_or_promotion(move); moved_piece = pos.moved_piece(move); - givesCheck = type_of(move) == NORMAL && !ci.dcCandidates - ? ci.checkSquares[type_of(pos.piece_on(from_sq(move)))] & to_sq(move) - : pos.gives_check(move, ci); + givesCheck = type_of(move) == NORMAL && !pos.discovered_check_candidates() + ? pos.check_squares(type_of(pos.piece_on(from_sq(move)))) & to_sq(move) + : pos.gives_check(move); moveCountPruning = depth < 16 * ONE_PLY - && moveCount >= FutilityMoveCounts[improving][depth]; + && moveCount >= FutilityMoveCounts[improving][depth / ONE_PLY]; // Step 12. Extend checks if ( givesCheck @@ -887,12 +902,13 @@ moves_loop: // When in check search starts from here if ( singularExtensionNode && move == ttMove && !extension - && pos.legal(move, ci.pinned)) + && pos.legal(move)) { Value rBeta = ttValue - 2 * depth / ONE_PLY; + Depth d = (depth / (2 * ONE_PLY)) * ONE_PLY; ss->excludedMove = move; ss->skipEarlyPruning = true; - value = search(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode); + value = search(pos, ss, rBeta - 1, rBeta, d, cutNode); ss->skipEarlyPruning = false; ss->excludedMove = MOVE_NONE; @@ -915,31 +931,38 @@ moves_loop: // When in check search starts from here if (moveCountPruning) continue; + predictedDepth = std::max(newDepth - reduction(improving, depth, moveCount), DEPTH_ZERO); + // Countermoves based pruning - if ( depth <= 4 * ONE_PLY + if ( predictedDepth < 3 * ONE_PLY && move != ss->killers[0] && (!cmh || (*cmh )[moved_piece][to_sq(move)] < VALUE_ZERO) && (!fmh || (*fmh )[moved_piece][to_sq(move)] < VALUE_ZERO) && (!fmh2 || (*fmh2)[moved_piece][to_sq(move)] < VALUE_ZERO || (cmh && fmh))) continue; - predictedDepth = std::max(newDepth - reduction(improving, depth, moveCount), DEPTH_ZERO); - // Futility pruning: parent node if ( predictedDepth < 7 * ONE_PLY - && ss->staticEval + futility_margin(predictedDepth) + 256 <= alpha) + && ss->staticEval + 256 + 200 * predictedDepth / ONE_PLY <= alpha) continue; - // Prune moves with negative SEE at low depths - if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < VALUE_ZERO) - continue; + // Prune moves with negative SEE at low depths and below a decreasing + // threshold at higher depths. + if (predictedDepth < 8 * ONE_PLY) + { + Value see_v = predictedDepth < 4 * ONE_PLY ? VALUE_ZERO + : -PawnValueMg * 2 * int(predictedDepth - 3 * ONE_PLY) / ONE_PLY; + + if (pos.see_sign(move) < see_v) + continue; + } } // Speculative prefetch as early as possible prefetch(TT.first_entry(pos.key_after(move))); // Check for legality just before making the move - if (!rootNode && !pos.legal(move, ci.pinned)) + if (!rootNode && !pos.legal(move)) { ss->moveCount = --moveCount; continue; @@ -955,36 +978,42 @@ moves_loop: // When in check search starts from here // re-searched at full depth. if ( depth >= 3 * ONE_PLY && moveCount > 1 - && !captureOrPromotion) + && (!captureOrPromotion || moveCountPruning)) { Depth r = reduction(improving, depth, moveCount); - Value val = thisThread->history[moved_piece][to_sq(move)] - + (cmh ? (*cmh )[moved_piece][to_sq(move)] : VALUE_ZERO) - + (fmh ? (*fmh )[moved_piece][to_sq(move)] : VALUE_ZERO) - + (fmh2 ? (*fmh2)[moved_piece][to_sq(move)] : VALUE_ZERO); - - // Increase reduction for cut nodes - if (cutNode) - r += 2 * ONE_PLY; - - // Decrease reduction for moves that escape a capture. Filter out - // castling moves, because they are coded as "king captures rook" and - // hence break make_move(). Also use see() instead of see_sign(), - // because the destination square is empty. - else if ( type_of(move) == NORMAL - && type_of(pos.piece_on(to_sq(move))) != PAWN - && pos.see(make_move(to_sq(move), from_sq(move))) < VALUE_ZERO) - r -= 2 * ONE_PLY; - - // Decrease/increase reduction for moves with a good/bad history - int rHist = (val - 10000) / 20000; - r = std::max(DEPTH_ZERO, r - rHist * ONE_PLY); + + if (captureOrPromotion) + r -= r ? ONE_PLY : DEPTH_ZERO; + else + { + // Increase reduction for cut nodes + if (cutNode) + r += 2 * ONE_PLY; + + // Decrease reduction for moves that escape a capture. Filter out + // castling moves, because they are coded as "king captures rook" and + // hence break make_move(). Also use see() instead of see_sign(), + // because the destination square is empty. + else if ( type_of(move) == NORMAL + && type_of(pos.piece_on(to_sq(move))) != PAWN + && pos.see(make_move(to_sq(move), from_sq(move))) < VALUE_ZERO) + r -= 2 * ONE_PLY; + + // Decrease/increase reduction for moves with a good/bad history + Value val = thisThread->history[moved_piece][to_sq(move)] + + (cmh ? (*cmh )[moved_piece][to_sq(move)] : VALUE_ZERO) + + (fmh ? (*fmh )[moved_piece][to_sq(move)] : VALUE_ZERO) + + (fmh2 ? (*fmh2)[moved_piece][to_sq(move)] : VALUE_ZERO) + + thisThread->fromTo.get(~pos.side_to_move(), move); + int rHist = (val - 8000) / 20000; + r = std::max(DEPTH_ZERO, (r / ONE_PLY - rHist) * ONE_PLY); + } Depth d = std::max(newDepth - r, ONE_PLY); value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); - doFullDepthSearch = (value > alpha && r != DEPTH_ZERO); + doFullDepthSearch = (value > alpha && d != newDepth); } else doFullDepthSearch = !PvNode || moveCount > 1; @@ -1098,27 +1127,34 @@ moves_loop: // When in check search starts from here if (!moveCount) bestValue = excludedMove ? alpha : inCheck ? mated_in(ss->ply) : DrawValue[pos.side_to_move()]; + else if (bestMove) + { + int d = depth / ONE_PLY; - // Quiet best move: update killers, history and countermoves - else if (bestMove && !pos.capture_or_promotion(bestMove)) - update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount); + // Quiet best move: update killers, history and countermoves + if (!pos.capture_or_promotion(bestMove)) + { + Value bonus = Value(d * d + 2 * d - 2); + update_stats(pos, ss, bestMove, quietsSearched, quietCount, bonus); + } + // Extra penalty for a quiet TT move in previous ply when it gets refuted + if ((ss-1)->moveCount == 1 && !pos.captured_piece_type()) + { + Value penalty = Value(d * d + 4 * d + 1); + Square prevSq = to_sq((ss-1)->currentMove); + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -penalty); + } + } // Bonus for prior countermove that caused the fail low else if ( depth >= 3 * ONE_PLY - && !bestMove && !pos.captured_piece_type() && is_ok((ss-1)->currentMove)) { + int d = depth / ONE_PLY; + Value bonus = Value(d * d + 2 * d - 2); Square prevSq = to_sq((ss-1)->currentMove); - Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + 2 * depth / ONE_PLY - 2); - if ((ss-2)->counterMoves) - (ss-2)->counterMoves->update(pos.piece_on(prevSq), prevSq, bonus); - - if ((ss-3)->counterMoves) - (ss-3)->counterMoves->update(pos.piece_on(prevSq), prevSq, bonus); - - if ((ss-5)->counterMoves) - (ss-5)->counterMoves->update(pos.piece_on(prevSq), prevSq, bonus); + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, bonus); } tte->save(posKey, value_to_tt(bestValue, ss->ply), @@ -1145,6 +1181,7 @@ moves_loop: // When in check search starts from here assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE); assert(PvNode || (alpha == beta - 1)); assert(depth <= DEPTH_ZERO); + assert(depth / ONE_PLY * ONE_PLY == depth); Move pv[MAX_PLY+1]; StateInfo st; @@ -1240,16 +1277,15 @@ moves_loop: // When in check search starts from here // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will // be generated. MovePicker mp(pos, ttMove, depth, to_sq((ss-1)->currentMove)); - CheckInfo ci(pos); // Loop through the moves until no moves remain or a beta cutoff occurs while ((move = mp.next_move()) != MOVE_NONE) { assert(is_ok(move)); - givesCheck = type_of(move) == NORMAL && !ci.dcCandidates - ? ci.checkSquares[type_of(pos.piece_on(from_sq(move)))] & to_sq(move) - : pos.gives_check(move, ci); + givesCheck = type_of(move) == NORMAL && !pos.discovered_check_candidates() + ? pos.check_squares(type_of(pos.piece_on(from_sq(move)))) & to_sq(move) + : pos.gives_check(move); // Futility pruning if ( !InCheck @@ -1289,7 +1325,7 @@ moves_loop: // When in check search starts from here prefetch(TT.first_entry(pos.key_after(move))); // Check for legality just before making the move - if (!pos.legal(move, ci.pinned)) + if (!pos.legal(move)) continue; ss->currentMove = move; @@ -1378,11 +1414,30 @@ moves_loop: // When in check search starts from here } + // update_cm_stats() updates countermove and follow-up move history + + void update_cm_stats(Stack* ss, Piece pc, Square s, Value bonus) { + + CounterMoveStats* cmh = (ss-1)->counterMoves; + CounterMoveStats* fmh1 = (ss-2)->counterMoves; + CounterMoveStats* fmh2 = (ss-4)->counterMoves; + + if (cmh) + cmh->update(pc, s, bonus); + + if (fmh1) + fmh1->update(pc, s, bonus); + + if (fmh2) + fmh2->update(pc, s, bonus); + } + + // update_stats() updates killers, history, countermove and countermove plus // follow-up move history when a new quiet best move is found. void update_stats(const Position& pos, Stack* ss, Move move, - Depth depth, Move* quiets, int quietsCnt) { + Move* quiets, int quietsCnt, Value bonus) { if (ss->killers[0] != move) { @@ -1390,54 +1445,24 @@ moves_loop: // When in check search starts from here ss->killers[0] = move; } - Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + 2 * depth / ONE_PLY - 2); - - Square prevSq = to_sq((ss-1)->currentMove); - CounterMoveStats* cmh = (ss-1)->counterMoves; - CounterMoveStats* fmh = (ss-2)->counterMoves; - CounterMoveStats* fmh2 = (ss-4)->counterMoves; + Color c = pos.side_to_move(); Thread* thisThread = pos.this_thread(); - + thisThread->fromTo.update(c, move, bonus); thisThread->history.update(pos.moved_piece(move), to_sq(move), bonus); + update_cm_stats(ss, pos.moved_piece(move), to_sq(move), bonus); - if (cmh) + if ((ss-1)->counterMoves) { + Square prevSq = to_sq((ss-1)->currentMove); thisThread->counterMoves.update(pos.piece_on(prevSq), prevSq, move); - cmh->update(pos.moved_piece(move), to_sq(move), bonus); } - if (fmh) - fmh->update(pos.moved_piece(move), to_sq(move), bonus); - - if (fmh2) - fmh2->update(pos.moved_piece(move), to_sq(move), bonus); - // Decrease all the other played quiet moves for (int i = 0; i < quietsCnt; ++i) { + thisThread->fromTo.update(c, quiets[i], -bonus); thisThread->history.update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); - - if (cmh) - cmh->update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); - - if (fmh) - fmh->update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); - - if (fmh2) - fmh2->update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); - } - - // Extra penalty for a quiet TT move in previous ply when it gets refuted - if ((ss-1)->moveCount == 1 && !pos.captured_piece_type()) - { - if ((ss-2)->counterMoves) - (ss-2)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1); - - if ((ss-3)->counterMoves) - (ss-3)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1); - - if ((ss-5)->counterMoves) - (ss-5)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1); + update_cm_stats(ss, pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); } } @@ -1572,7 +1597,7 @@ bool RootMove::extract_ponder_from_tt(Position& pos) assert(pv.size() == 1); - pos.do_move(pv[0], st, pos.gives_check(pv[0], CheckInfo(pos))); + pos.do_move(pv[0], st, pos.gives_check(pv[0])); TTEntry* tte = TT.probe(pos.key(), ttHit); if (ttHit)