From: bmc4 Date: Mon, 20 Dec 2021 19:20:08 +0000 (-0300) Subject: Update Elo estimates for terms in search X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=88f17a814d80cdb32ccf9efb7b56bb36d7bf052b Update Elo estimates for terms in search This updates estimates from 2yr ago #2401, and adds missing terms. All tests run at 10+0.1 (STC), 20000 games, error bars +- 1.8 Elo, book 8moves_v3.png. A table of Elo values with the links to the corresponding tests can be found at the PR closes https://github.com/official-stockfish/Stockfish/pull/3868 Non-functional Change --- diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 24445f48..28689f1d 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -1083,7 +1083,7 @@ Value Eval::evaluate(const Position& pos) { Value v; - // Deciding between classical and NNUE eval: for high PSQ imbalance we use classical, + // Deciding between classical and NNUE eval (~10 Elo): for high PSQ imbalance we use classical, // but we switch to NNUE during long shuffling or with high material on the board. if ( !useNNUE diff --git a/src/search.cpp b/src/search.cpp index 988166df..f5e9779c 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -671,20 +671,20 @@ namespace { && (ttValue >= beta ? (tte->bound() & BOUND_LOWER) : (tte->bound() & BOUND_UPPER))) { - // If ttMove is quiet, update move sorting heuristics on TT hit + // If ttMove is quiet, update move sorting heuristics on TT hit (~1 Elo) if (ttMove) { if (ttValue >= beta) { - // Bonus for a quiet ttMove that fails high + // Bonus for a quiet ttMove that fails high (~3 Elo) if (!ttCapture) update_quiet_stats(pos, ss, ttMove, stat_bonus(depth)); - // Extra penalty for early quiet moves of the previous ply + // Extra penalty for early quiet moves of the previous ply (~0 Elo) if ((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 + // Penalty for a quiet ttMove that fails low (~1 Elo) else if (!ttCapture) { int penalty = -stat_bonus(depth); @@ -773,7 +773,7 @@ namespace { if (eval == VALUE_DRAW) eval = value_draw(thisThread); - // Can ttValue be used as a better position evaluation? + // ttValue can be used as a better position evaluation (~4 Elo) if ( ttValue != VALUE_NONE && (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER))) eval = ttValue; @@ -787,7 +787,7 @@ namespace { tte->save(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval); } - // Use static evaluation difference to improve quiet move ordering + // Use static evaluation difference to improve quiet move ordering (~3 Elo) if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture) { int bonus = std::clamp(-16 * int((ss-1)->staticEval + ss->staticEval), -2000, 2000); @@ -804,7 +804,7 @@ namespace { improving = improvement > 0; - // Step 7. Futility pruning: child node (~50 Elo). + // Step 7. Futility pruning: child node (~25 Elo). // The depth condition is important for mate finding. if ( !ss->ttPv && depth < 9 @@ -812,7 +812,7 @@ namespace { && eval < 15000) // 50% larger than VALUE_KNOWN_WIN, but smaller than TB wins. return eval; - // Step 8. Null move search with verification search (~40 Elo) + // Step 8. Null move search with verification search (~22 Elo) if ( !PvNode && (ss-1)->currentMove != MOVE_NULL && (ss-1)->statScore < 23767 @@ -925,7 +925,7 @@ namespace { ss->ttPv = ttPv; } - // Step 10. If the position is not in TT, decrease depth by 2 or 1 depending on node type + // Step 10. If the position is not in TT, decrease depth by 2 or 1 depending on node type (~3 Elo) if ( PvNode && depth >= 6 && !ttMove) @@ -940,7 +940,7 @@ moves_loop: // When in check, search starts here int rangeReduction = 0; - // Step 11. A small Probcut idea, when we are in check + // Step 11. A small Probcut idea, when we are in check (~0 Elo) probCutBeta = beta + 409; if ( ss->inCheck && !PvNode @@ -1017,12 +1017,12 @@ moves_loop: // When in check, search starts here Value delta = beta - alpha; - // Step 13. Pruning at shallow depth (~200 Elo). Depth conditions are important for mate finding. + // Step 13. Pruning at shallow depth (~98 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 + // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~7 Elo) moveCountPruning = moveCount >= futility_move_count(improving, depth); // Reduced depth of the next LMR search @@ -1031,18 +1031,18 @@ moves_loop: // When in check, search starts here if ( captureOrPromotion || givesCheck) { - // Futility pruning for captures + // Futility pruning for captures (~0 Elo) if ( !pos.empty(to_sq(move)) && !givesCheck && !PvNode && lmrDepth < 6 && !ss->inCheck - && ss->staticEval + 342 + 238 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))] + && ss->staticEval + 342 + 238 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))] + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 8 < alpha) continue; - // SEE based pruning - if (!pos.see_ge(move, Value(-218) * depth)) // (~25 Elo) + // SEE based pruning (~9 Elo) + if (!pos.see_ge(move, Value(-218) * depth)) continue; } else @@ -1051,28 +1051,28 @@ moves_loop: // When in check, search starts here + (*contHist[1])[movedPiece][to_sq(move)] + (*contHist[3])[movedPiece][to_sq(move)]; - // Continuation history based pruning (~20 Elo) + // Continuation history based pruning (~2 Elo) if ( lmrDepth < 5 && history < -3000 * depth + 3000) continue; history += thisThread->mainHistory[us][from_to(move)]; - // Futility pruning: parent node (~5 Elo) + // Futility pruning: parent node (~9 Elo) if ( !ss->inCheck && lmrDepth < 8 && ss->staticEval + 142 + 139 * lmrDepth + history / 64 <= alpha) continue; - // Prune moves with negative SEE (~20 Elo) + // Prune moves with negative SEE (~3 Elo) if (!pos.see_ge(move, Value(-21 * lmrDepth * lmrDepth - 21 * lmrDepth))) continue; } } - // Step 14. Extensions (~75 Elo) + // Step 14. Extensions (~66 Elo) - // Singular extension search (~70 Elo). If all moves but one fail low on a + // Singular extension search (~58 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 @@ -1117,13 +1117,13 @@ moves_loop: // When in check, search starts here extension = -2; } - // Check extensions + // Check extensions (~1 Elo) else if ( givesCheck && depth > 6 && abs(ss->staticEval) > 100) extension = 1; - // Quiet ttMove extensions + // Quiet ttMove extensions (~0 Elo) else if ( PvNode && move == ttMove && move == ss->killers[0] @@ -1149,7 +1149,7 @@ moves_loop: // When in check, search starts here bool doDeeperSearch = false; - // Step 16. Late moves reduction / extension (LMR, ~200 Elo) + // Step 16. Late moves reduction / extension (LMR, ~98 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". @@ -1467,7 +1467,7 @@ moves_loop: // When in check, search starts here if ((ss->staticEval = bestValue = tte->eval()) == VALUE_NONE) ss->staticEval = bestValue = evaluate(pos); - // Can ttValue be used as a better position evaluation? + // ttValue can be used as a better position evaluation (~7 Elo) if ( ttValue != VALUE_NONE && (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER))) bestValue = ttValue; @@ -1522,7 +1522,7 @@ moves_loop: // When in check, search starts here moveCount++; - // Futility pruning and moveCount pruning + // Futility pruning and moveCount pruning (~5 Elo) if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY && !givesCheck && futilityBase > -VALUE_KNOWN_WIN @@ -1547,7 +1547,7 @@ moves_loop: // When in check, search starts here } } - // Do not search moves with negative SEE values + // Do not search moves with negative SEE values (~5 Elo) if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY && !pos.see_ge(move)) continue; @@ -1561,7 +1561,7 @@ moves_loop: // When in check, search starts here [pos.moved_piece(move)] [to_sq(move)]; - // Continuation history based pruning + // Continuation history based pruning (~2 Elo) if ( !captureOrPromotion && bestValue > VALUE_TB_LOSS_IN_MAX_PLY && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold