From 5254a6040c59cf7d3b9faa847168ccbd628c0574 Mon Sep 17 00:00:00 2001 From: VoyagerOne Date: Wed, 25 Jan 2017 09:32:10 -0500 Subject: [PATCH] Penalty for a quiet ttMove that fails low Also the penalty/bonus function is misleading, we should simply change it to stat_bonus(depth) for bonus and -stat_bonus(depth+ ONE_PLY) for extra penalty. STC: LLR: 2.96 (-2.94,2.94) [0.00,5.00] Total: 11656 W: 2183 L: 2008 D: 7465 LTC: LLR: 2.95 (-2.94,2.94) [0.00,5.00] Total: 11152 W: 1531 L: 1377 D: 8244 Bench: 6101931 --- src/search.cpp | 39 ++++++++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 13 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index a7dbd90d..b75870ff 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -75,6 +75,12 @@ namespace { return Reductions[PvNode][i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] * ONE_PLY; } + // History and stats update bonus, based on depth + Value stat_bonus(Depth depth) { + int d = depth / ONE_PLY ; + return Value(d * d + 2 * d - 2); + } + // Skill structure is used to implement strength limit struct Skill { Skill(int l) : level(l) {} @@ -155,9 +161,6 @@ namespace { const size_t HalfDensitySize = std::extent::value; - Value bonus(Depth depth) { int d = depth / ONE_PLY ; return Value(d * d + 2 * d - 2); } - Value penalty(Depth depth) { int d = depth / ONE_PLY ; return -Value(d * d + 4 * d + 1); } - EasyMoveManager EasyMove; Value DrawValue[COLOR_NB]; @@ -642,14 +645,24 @@ namespace { : (tte->bound() & BOUND_UPPER))) { // If ttMove is quiet, update move sorting heuristics on TT hit - if (ttValue >= beta && ttMove) + if (ttMove) { - if (!pos.capture_or_promotion(ttMove)) - update_stats(pos, ss, ttMove, nullptr, 0, bonus(depth)); + if (ttValue >= beta) + { + if (!pos.capture_or_promotion(ttMove)) + update_stats(pos, ss, ttMove, nullptr, 0, stat_bonus(depth)); - // Extra penalty for a quiet TT move in previous ply when it gets refuted - if ((ss-1)->moveCount == 1 && !pos.captured_piece()) - update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, penalty(depth)); + // Extra penalty for a quiet TT move in previous ply when it gets refuted + if ((ss-1)->moveCount == 1 && !pos.captured_piece()) + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY)); + } + // Penalty for a quiet ttMove that fails low + else if (ttValue < alpha && !pos.capture_or_promotion(ttMove)) + { + Value penalty = -stat_bonus(depth + ONE_PLY); + thisThread->history.update(pos.side_to_move(), ttMove, penalty); + update_cm_stats(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty); + } } return ttValue; } @@ -988,7 +1001,7 @@ moves_loop: // When in check search starts from here + (fmh ? (*fmh )[moved_piece][to_sq(move)] : VALUE_ZERO) + (fmh2 ? (*fmh2)[moved_piece][to_sq(move)] : VALUE_ZERO) + thisThread->history.get(~pos.side_to_move(), move) - - 8000; // Correction factor + - 4000; // Correction factor // Decrease/increase reduction by comparing opponent's stat score if (ss->history > VALUE_ZERO && (ss-1)->history < VALUE_ZERO) @@ -1120,17 +1133,17 @@ moves_loop: // When in check search starts from here // Quiet best move: update move sorting heuristics if (!pos.capture_or_promotion(bestMove)) - update_stats(pos, ss, bestMove, quietsSearched, quietCount, bonus(depth)); + update_stats(pos, ss, bestMove, quietsSearched, quietCount, stat_bonus(depth)); // Extra penalty for a quiet TT move in previous ply when it gets refuted if ((ss-1)->moveCount == 1 && !pos.captured_piece()) - update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, penalty(depth)); + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY)); } // Bonus for prior countermove that caused the fail low else if ( depth >= 3 * ONE_PLY && !pos.captured_piece() && is_ok((ss-1)->currentMove)) - update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, bonus(depth)); + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth)); tte->save(posKey, value_to_tt(bestValue, ss->ply), bestValue >= beta ? BOUND_LOWER : -- 2.39.2