X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=17c1c28b2646eadd6ec565892f7f0a39620a92a4;hb=af4b62a593cc4fa6d7d34110c41301028a5c9695;hp=a41ea4fd269ed6b5ad97159f30ac8e82a7ef16c0;hpb=472e726bff0d0e496dc8359cc071726a76317a72;p=stockfish diff --git a/src/search.cpp b/src/search.cpp index a41ea4fd..17c1c28b 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -34,6 +34,7 @@ #include "tt.h" #include "uci.h" #include "syzygy/tbprobe.h" +#include "nnue/evaluate_nnue.h" namespace Stockfish { @@ -334,7 +335,7 @@ void Thread::search() { pvLast = 0; if (!Threads.increaseDepth) - searchAgainCounter++; + searchAgainCounter++; // MultiPV loop. We perform a full root search for each PV line for (pvIdx = 0; pvIdx < multiPV && !Threads.stop; ++pvIdx) @@ -432,9 +433,10 @@ void Thread::search() { if (!Threads.stop) completedDepth = rootDepth; - if (rootMoves[0].pv[0] != lastBestMove) { - lastBestMove = rootMoves[0].pv[0]; - lastBestMoveDepth = rootDepth; + if (rootMoves[0].pv[0] != lastBestMove) + { + lastBestMove = rootMoves[0].pv[0]; + lastBestMoveDepth = rootDepth; } // Have we found a "mate in x"? @@ -600,12 +602,11 @@ namespace { assert(0 <= ss->ply && ss->ply < MAX_PLY); - (ss+1)->ttPv = false; (ss+1)->excludedMove = bestMove = MOVE_NONE; (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; (ss+2)->cutoffCnt = 0; ss->doubleExtensions = (ss-1)->doubleExtensions; - Square prevSq = to_sq((ss-1)->currentMove); + Square prevSq = is_ok((ss-1)->currentMove) ? to_sq((ss-1)->currentMove) : SQ_NONE; // Initialize statScore to zero for the grandchildren of the current position. // So statScore is shared between all grandchildren and only the first grandchild @@ -622,7 +623,7 @@ namespace { ttValue = ss->ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE; ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0] : ss->ttHit ? tte->move() : MOVE_NONE; - ttCapture = ttMove && pos.capture(ttMove); + ttCapture = ttMove && pos.capture_stage(ttMove); // At this point, if excluded, skip straight to step 6, static eval. However, // to save indentation, we list the condition in all code between here and there. @@ -647,7 +648,7 @@ namespace { update_quiet_stats(pos, ss, ttMove, stat_bonus(depth)); // Extra penalty for early quiet moves of the previous ply (~0 Elo on STC, ~2 Elo on LTC) - if ((ss-1)->moveCount <= 2 && !priorCapture) + if (prevSq != SQ_NONE && (ss-1)->moveCount <= 2 && !priorCapture) update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1)); } // Penalty for a quiet ttMove that fails low (~1 Elo) @@ -729,7 +730,8 @@ namespace { complexity = 0; goto moves_loop; } - else if (excludedMove) { + else if (excludedMove) + { // Providing the hint that this node's accumulator will be used often brings significant Elo gain (13 elo) Eval::NNUE::hint_common_parent_position(pos); eval = ss->staticEval; @@ -742,7 +744,11 @@ namespace { if (eval == VALUE_NONE) ss->staticEval = eval = evaluate(pos, &complexity); else // Fall back to (semi)classical complexity for TT hits, the NNUE complexity is lost + { complexity = abs(ss->staticEval - pos.psq_eg_stm()); + if (PvNode) + Eval::NNUE::hint_common_parent_position(pos); + } // ttValue can be used as a better position evaluation (~7 Elo) if ( ttValue != VALUE_NONE @@ -755,6 +761,7 @@ namespace { // Save static evaluation into transposition table tte->save(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval); } + thisThread->complexityAverage.update(complexity); // Use static evaluation difference to improve quiet move ordering (~4 Elo) @@ -845,7 +852,7 @@ namespace { probCutBeta = beta + 186 - 54 * improving; // Step 10. ProbCut (~10 Elo) - // If we have a good enough capture and a reduced search returns a value + // If we have a good enough capture (or queen promotion) and a reduced search returns a value // much above beta, we can (almost) safely prune the previous move. if ( !PvNode && depth > 4 @@ -866,7 +873,7 @@ namespace { while ((move = mp.next_move()) != MOVE_NONE) if (move != excludedMove && pos.legal(move)) { - assert(pos.capture(move) || promotion_type(move) == QUEEN); + assert(pos.capture_stage(move)); ss->currentMove = move; ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck] @@ -892,6 +899,8 @@ namespace { return value; } } + + Eval::NNUE::hint_common_parent_position(pos); } // Step 11. If the position is not in TT, decrease depth by 3. @@ -920,16 +929,14 @@ moves_loop: // When in check, search starts here && tte->depth() >= depth - 3 && ttValue >= probCutBeta && abs(ttValue) <= VALUE_KNOWN_WIN - && abs(beta) <= VALUE_KNOWN_WIN - ) + && abs(beta) <= VALUE_KNOWN_WIN) return probCutBeta; - const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, nullptr , (ss-4)->continuationHistory, nullptr , (ss-6)->continuationHistory }; - Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]; + Move countermove = prevSq != SQ_NONE ? thisThread->counterMoves[pos.piece_on(prevSq)][prevSq] : MOVE_NONE; MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, &captureHistory, @@ -978,7 +985,7 @@ moves_loop: // When in check, search starts here (ss+1)->pv = nullptr; extension = 0; - capture = pos.capture(move); + capture = pos.capture_stage(move); movedPiece = pos.moved_piece(move); givesCheck = pos.gives_check(move); @@ -1064,11 +1071,10 @@ moves_loop: // When in check, search starts here && (tte->bound() & BOUND_LOWER) && tte->depth() >= depth - 3) { - Value singularBeta = ttValue - (2 + (ss->ttPv && !PvNode)) * depth; + Value singularBeta = ttValue - (3 + 2 * (ss->ttPv && !PvNode)) * depth / 2; Depth singularDepth = (depth - 1) / 2; ss->excludedMove = move; - // the search with excludedMove will update ss->staticEval value = search(pos, ss, singularBeta - 1, singularBeta, singularDepth, cutNode); ss->excludedMove = MOVE_NONE; @@ -1097,10 +1103,14 @@ moves_loop: // When in check, search starts here // If the eval of ttMove is greater than beta, we reduce it (negative extension) else if (ttValue >= beta) - extension = -2; + extension = -2 - !PvNode; + + // If the eval of ttMove is less than value, we reduce it (negative extension) + else if (ttValue <= value) + extension = -1; - // If the eval of ttMove is less than alpha and value, we reduce it (negative extension) - else if (ttValue <= alpha && ttValue <= value) + // If the eval of ttMove is less than alpha, we reduce it (negative extension) + else if (ttValue <= alpha) extension = -1; } @@ -1227,11 +1237,11 @@ moves_loop: // When in check, search starts here // Step 18. Full depth search when LMR is skipped. If expected reduction is high, reduce its depth by 1. else if (!PvNode || moveCount > 1) { - // Increase reduction for cut nodes and not ttMove (~1 Elo) - if (!ttMove && cutNode) - r += 2; + // Increase reduction for cut nodes and not ttMove (~1 Elo) + if (!ttMove && cutNode) + r += 2; - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth - (r > 4), !cutNode); + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth - (r > 4), !cutNode); } // For PV nodes only, do a full PV search on the first move or after a fail @@ -1271,14 +1281,17 @@ moves_loop: // When in check, search starts here rm.selDepth = thisThread->selDepth; rm.scoreLowerbound = rm.scoreUpperbound = false; - if (value >= beta) { - rm.scoreLowerbound = true; - rm.uciScore = beta; + if (value >= beta) + { + rm.scoreLowerbound = true; + rm.uciScore = beta; } - else if (value <= alpha) { - rm.scoreUpperbound = true; - rm.uciScore = alpha; + else if (value <= alpha) + { + rm.scoreUpperbound = true; + rm.uciScore = alpha; } + rm.pv.resize(1); assert((ss+1)->pv); @@ -1371,10 +1384,9 @@ moves_loop: // When in check, search starts here quietsSearched, quietCount, capturesSearched, captureCount, depth); // Bonus for prior countermove that caused the fail low - else if (!priorCapture) + else if (!priorCapture && prevSq != SQ_NONE) { - // Extra bonuses for PV/Cut nodes or bad fail lows - int bonus = (depth > 5) + (PvNode || cutNode) + (bestValue < alpha - 97 * depth); + int bonus = (depth > 5) + (PvNode || cutNode) + (bestValue < alpha - 97 * depth) + ((ss-1)->moveCount > 10); update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * bonus); } @@ -1447,7 +1459,8 @@ moves_loop: // When in check, search starts here // TT entry depth that we are going to use. Note that in qsearch we use // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS. ttDepth = ss->inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS - : DEPTH_QS_NO_CHECKS; + : DEPTH_QS_NO_CHECKS; + // Step 3. Transposition table lookup posKey = pos.key(); tte = TT.probe(posKey, ss->ttHit); @@ -1513,7 +1526,7 @@ moves_loop: // When in check, search starts here // to search the moves. Because the depth is <= 0 here, only captures, // queen promotions, and other checks (only if depth >= DEPTH_QS_CHECKS) // will be generated. - Square prevSq = to_sq((ss-1)->currentMove); + Square prevSq = (ss-1)->currentMove != MOVE_NULL ? to_sq((ss-1)->currentMove) : SQ_NONE; MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, &thisThread->captureHistory, contHist, @@ -1532,7 +1545,7 @@ moves_loop: // When in check, search starts here continue; givesCheck = pos.gives_check(move); - capture = pos.capture(move); + capture = pos.capture_stage(move); moveCount++; @@ -1577,7 +1590,6 @@ moves_loop: // When in check, search starts here // Do not search moves with bad enough SEE values (~5 Elo) if (!pos.see_ge(move, Value(-110))) continue; - } // Speculative prefetch as early as possible @@ -1703,10 +1715,11 @@ moves_loop: // When in check, search starts here Thread* thisThread = pos.this_thread(); CapturePieceToHistory& captureHistory = thisThread->captureHistory; Piece moved_piece = pos.moved_piece(bestMove); - PieceType captured = type_of(pos.piece_on(to_sq(bestMove))); + PieceType captured; + int bonus1 = stat_bonus(depth + 1); - if (!pos.capture(bestMove)) + if (!pos.capture_stage(bestMove)) { int bonus2 = bestValue > beta + 153 ? bonus1 // larger bonus : stat_bonus(depth); // smaller bonus @@ -1722,12 +1735,16 @@ moves_loop: // When in check, search starts here } } else + { // Increase stats for the best move in case it was a capture move + captured = type_of(pos.piece_on(to_sq(bestMove))); captureHistory[moved_piece][to_sq(bestMove)][captured] << bonus1; + } // Extra penalty for a quiet early move that was not a TT move or // main killer move in previous ply when it gets refuted. - if ( ((ss-1)->moveCount == 1 + (ss-1)->ttHit || ((ss-1)->currentMove == (ss-1)->killers[0])) + if ( prevSq != SQ_NONE + && ((ss-1)->moveCount == 1 + (ss-1)->ttHit || ((ss-1)->currentMove == (ss-1)->killers[0])) && !pos.captured_piece()) update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -bonus1);