X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=ed5dd6c2c7ad5aab3e39b26cb038833c3a6b58d2;hb=b7b6b4ba18bc9d291c2c2fd300c22a3e008dcbb2;hp=af8ddaba5a420887d0c5a98907b7ca975d4b802d;hpb=a1a83f38691ae3f39c827a46e59ae9875605aa3b;p=stockfish diff --git a/src/search.cpp b/src/search.cpp index af8ddaba..ed5dd6c2 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -779,8 +779,10 @@ namespace { ? ss->staticEval > (ss-4)->staticEval || (ss-4)->staticEval == VALUE_NONE : ss->staticEval > (ss-2)->staticEval; - // Step 7. Futility pruning: child node (~50 Elo) + // Step 7. Futility pruning: child node (~50 Elo). + // The depth condition is important for mate finding. if ( !PvNode + && depth < 9 && eval - futility_margin(depth, improving) >= beta && eval < VALUE_KNOWN_WIN) // Do not return unproven wins return eval; @@ -799,7 +801,7 @@ namespace { assert(eval - beta >= 0); // Null move dynamic reduction based on depth and value - Depth R = (1090 + 81 * depth) / 256 + std::min(int(eval - beta) / 205, 3); + Depth R = std::min(int(eval - beta) / 205, 3) + depth / 3 + 4; ss->currentMove = MOVE_NULL; ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0]; @@ -989,7 +991,7 @@ moves_loop: // When in check, search starts here // Calculate new depth for this move newDepth = depth - 1; - // Step 13. Pruning at shallow depth (~200 Elo) + // Step 13. Pruning at shallow depth (~200 Elo). Depth conditions are important for mate finding. if ( !rootNode && pos.non_pawn_material(us) && bestValue > VALUE_TB_LOSS_IN_MAX_PLY) @@ -1016,13 +1018,15 @@ moves_loop: // When in check, search starts here else { // Continuation history based pruning (~20 Elo) - if ( lmrDepth < 5 - && (*contHist[0])[movedPiece][to_sq(move)] < 23 - 23 * depth * depth - && (*contHist[1])[movedPiece][to_sq(move)] < 23 - 23 * depth * depth) + if (lmrDepth < 5 + && (*contHist[0])[movedPiece][to_sq(move)] + + (*contHist[1])[movedPiece][to_sq(move)] + + (*contHist[3])[movedPiece][to_sq(move)] < -3000 * depth + 3000) continue; // Futility pruning: parent node (~5 Elo) if ( !ss->inCheck + && lmrDepth < 7 && ss->staticEval + 174 + 157 * lmrDepth <= alpha) continue; @@ -1090,6 +1094,14 @@ moves_loop: // When in check, search starts here return beta; } } + + // Capture extensions for PvNodes and cutNodes + else if ( (PvNode || cutNode) + && captureOrPromotion + && moveCount != 1) + extension = 1; + + // Check extensions else if ( givesCheck && depth > 6 && abs(ss->staticEval) > Value(100)) @@ -1170,8 +1182,8 @@ moves_loop: // When in check, search starts here // In general we want to cap the LMR depth search at newDepth. But if // reductions are really negative and movecount is low, we allow this move - // to be searched deeper than the first move, unless ttMove was extended by 2. - Depth d = std::clamp(newDepth - r, 1, newDepth + (r < -1 && moveCount <= 5 && !doubleExtension)); + // to be searched deeper than the first move in specific cases. + Depth d = std::clamp(newDepth - r, 1, newDepth + (r < -1 && (moveCount <= 5 || (depth > 6 && PvNode)) && !doubleExtension)); value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); @@ -1313,7 +1325,7 @@ moves_loop: // When in check, search starts here // Bonus for prior countermove that caused the fail low else if ( (depth >= 3 || PvNode) && !priorCapture) - update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth)); + update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + (PvNode || cutNode))); if (PvNode) bestValue = std::min(bestValue, maxValue);