From b2bd8699eccc149cdda1f7bf6e1eed42088ec827 Mon Sep 17 00:00:00 2001 From: FauziAkram Date: Tue, 20 Dec 2022 22:54:12 +0300 Subject: [PATCH] Update Elo estimates for terms in search based on 25k games per term, using the UHO_XXL_+0.90_+1.19.epd book, at STC. More detailed information in the PR. closes https://github.com/official-stockfish/Stockfish/pull/4294 No functional change --- src/search.cpp | 48 ++++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 7f2f5284..77d23ac2 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -633,16 +633,16 @@ namespace { && ttValue != VALUE_NONE // Possible in case of TT access race && (tte->bound() & (ttValue >= beta ? BOUND_LOWER : BOUND_UPPER))) { - // If ttMove is quiet, update move sorting heuristics on TT hit (~1 Elo) + // If ttMove is quiet, update move sorting heuristics on TT hit (~2 Elo) if (ttMove) { if (ttValue >= beta) { - // Bonus for a quiet ttMove that fails high (~3 Elo) + // Bonus for a quiet ttMove that fails high (~2 Elo) if (!ttCapture) update_quiet_stats(pos, ss, ttMove, stat_bonus(depth)); - // Extra penalty for early quiet moves of the previous ply (~0 Elo) + // Extra penalty for early quiet moves of the previous ply (~0 Elo on STC, ~2 Elo on LTC) if ((ss-1)->moveCount <= 2 && !priorCapture) update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1)); } @@ -734,7 +734,7 @@ namespace { else // Fall back to (semi)classical complexity for TT hits, the NNUE complexity is lost complexity = abs(ss->staticEval - pos.psq_eg_stm()); - // ttValue can be used as a better position evaluation (~4 Elo) + // ttValue can be used as a better position evaluation (~7 Elo) if ( ttValue != VALUE_NONE && (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER))) eval = ttValue; @@ -750,7 +750,7 @@ namespace { thisThread->complexityAverage.update(complexity); - // Use static evaluation difference to improve quiet move ordering (~3 Elo) + // Use static evaluation difference to improve quiet move ordering (~4 Elo) if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture) { int bonus = std::clamp(-19 * int((ss-1)->staticEval + ss->staticEval), -1914, 1914); @@ -766,7 +766,7 @@ namespace { : 168; improving = improvement > 0; - // Step 7. Razoring. + // Step 7. Razoring (~1 Elo). // If eval is really low check with qsearch if it can exceed alpha, if it can't, // return a fail low. if (eval < alpha - 369 - 254 * depth * depth) @@ -776,7 +776,7 @@ namespace { return value; } - // Step 8. Futility pruning: child node (~25 Elo). + // Step 8. Futility pruning: child node (~40 Elo). // The depth condition is important for mate finding. if ( !ss->ttPv && depth < 8 @@ -785,7 +785,7 @@ namespace { && eval < 28031) // larger than VALUE_KNOWN_WIN, but smaller than TB wins return eval; - // Step 9. Null move search with verification search (~22 Elo) + // Step 9. Null move search with verification search (~35 Elo) if ( !PvNode && (ss-1)->currentMove != MOVE_NULL && (ss-1)->statScore < 17139 @@ -837,7 +837,7 @@ namespace { probCutBeta = beta + 191 - 54 * improving; - // Step 10. ProbCut (~4 Elo) + // Step 10. ProbCut (~10 Elo) // 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 @@ -888,7 +888,7 @@ namespace { } // Step 11. If the position is not in TT, decrease depth by 3. - // Use qsearch if depth is equal or below zero (~4 Elo) + // Use qsearch if depth is equal or below zero (~9 Elo) if ( PvNode && !ttMove) depth -= 3; @@ -903,7 +903,7 @@ namespace { moves_loop: // When in check, search starts here - // Step 12. A small Probcut idea, when we are in check (~0 Elo) + // Step 12. A small Probcut idea, when we are in check (~4 Elo) probCutBeta = beta + 417; if ( ss->inCheck && !PvNode @@ -980,12 +980,12 @@ moves_loop: // When in check, search starts here Value delta = beta - alpha; - // Step 14. Pruning at shallow depth (~98 Elo). Depth conditions are important for mate finding. + // Step 14. Pruning at shallow depth (~120 Elo). Depth conditions are important for mate finding. if ( !rootNode && pos.non_pawn_material(us) && bestValue > VALUE_TB_LOSS_IN_MAX_PLY) { - // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~7 Elo) + // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~8 Elo) moveCountPruning = moveCount >= futility_move_count(improving, depth); // Reduced depth of the next LMR search @@ -994,7 +994,7 @@ moves_loop: // When in check, search starts here if ( capture || givesCheck) { - // Futility pruning for captures (~0 Elo) + // Futility pruning for captures (~2 Elo) if ( !givesCheck && !PvNode && lmrDepth < 7 @@ -1003,7 +1003,7 @@ moves_loop: // When in check, search starts here + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 6 < alpha) continue; - // SEE based pruning (~9 Elo) + // SEE based pruning (~11 Elo) if (!pos.see_ge(move, Value(-222) * depth)) continue; } @@ -1020,23 +1020,23 @@ moves_loop: // When in check, search starts here history += 2 * thisThread->mainHistory[us][from_to(move)]; - // Futility pruning: parent node (~9 Elo) + // Futility pruning: parent node (~13 Elo) if ( !ss->inCheck && lmrDepth < 13 && ss->staticEval + 106 + 145 * lmrDepth + history / 52 <= alpha) continue; - // Prune moves with negative SEE (~3 Elo) + // Prune moves with negative SEE (~4 Elo) if (!pos.see_ge(move, Value(-24 * lmrDepth * lmrDepth - 15 * lmrDepth))) continue; } } - // Step 15. Extensions (~66 Elo) + // Step 15. Extensions (~100 Elo) // We take care to not overdo to avoid search getting stuck. if (ss->ply < thisThread->rootDepth * 2) { - // Singular extension search (~58 Elo). If all moves but one fail low on a + // Singular extension search (~94 Elo). If all moves but one fail low on a // search of (alpha-s, beta-s), and just one fails high on (alpha, beta), // then that move is singular and should be extended. To verify this we do // a reduced search on all the other moves but the ttMove and if the @@ -1095,7 +1095,7 @@ moves_loop: // When in check, search starts here && abs(ss->staticEval) > 82) extension = 1; - // Quiet ttMove extensions (~0 Elo) + // Quiet ttMove extensions (~1 Elo) else if ( PvNode && move == ttMove && move == ss->killers[0] @@ -1166,7 +1166,7 @@ moves_loop: // When in check, search starts here // Decrease/increase reduction for moves with a good/bad history (~30 Elo) r -= ss->statScore / (13000 + 4152 * (depth > 7 && depth < 19)); - // Step 17. Late moves reduction / extension (LMR, ~98 Elo) + // Step 17. Late moves reduction / extension (LMR, ~117 Elo) // We use various heuristics for the sons of a node after the first son has // been searched. In general we would like to reduce them, but there are many // cases where we extend a son if it has good chances to be "interesting". @@ -1462,7 +1462,7 @@ moves_loop: // When in check, search starts here if ((ss->staticEval = bestValue = tte->eval()) == VALUE_NONE) ss->staticEval = bestValue = evaluate(pos); - // ttValue can be used as a better position evaluation (~7 Elo) + // ttValue can be used as a better position evaluation (~13 Elo) if ( ttValue != VALUE_NONE && (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER))) bestValue = ttValue; @@ -1520,7 +1520,7 @@ moves_loop: // When in check, search starts here moveCount++; - // Futility pruning and moveCount pruning (~5 Elo) + // Futility pruning and moveCount pruning (~10 Elo) if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY && !givesCheck && to_sq(move) != prevSq @@ -1559,7 +1559,7 @@ moves_loop: // When in check, search starts here [pos.moved_piece(move)] [to_sq(move)]; - // Continuation history based pruning (~2 Elo) + // Continuation history based pruning (~3 Elo) if ( !capture && bestValue > VALUE_TB_LOSS_IN_MAX_PLY && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < 0 -- 2.39.2