X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=d0ea367a19e9bba7a64bafe1db06d88d6be30bc6;hp=c187c3ad6ee8a914ea9eb0904e89cc8dbff47374;hb=b1b19343cd1f5ec65084dc11a0a0b4d5ece2a24b;hpb=3686e719a14a49f54bff00b3df153e044a0206ab diff --git a/src/movepick.cpp b/src/movepick.cpp index c187c3ad..d0ea367a 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -2,7 +2,7 @@ Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad - Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -34,27 +34,30 @@ namespace { QSEARCH_RECAPTURES, QRECAPTURES }; - // Our insertion sort, which is guaranteed to be stable, as it should be - void insertion_sort(ExtMove* begin, ExtMove* end) - { - ExtMove tmp, *p, *q; - - for (p = begin + 1; p < end; ++p) - { - tmp = *p; - for (q = p; q != begin && *(q-1) < tmp; --q) - *q = *(q-1); - *q = tmp; - } + // partial_insertion_sort() sorts moves in descending order up to and including + // a given limit. The order of moves smaller than the limit is left unspecified. + // To keep the implementation simple, *begin is always included in the sorted moves. + void partial_insertion_sort(ExtMove* begin, ExtMove* end, int limit) { + + for (ExtMove *sortedEnd = begin + 1, *p = begin + 1; p < end; ++p) + if (p->value >= limit) + { + ExtMove tmp = *p, *q; + *p = *sortedEnd; + for (q = sortedEnd; q != begin && *(q-1) < tmp; --q) + *q = *(q-1); + *q = tmp; + ++sortedEnd; + } } // pick_best() finds the best move in the range (begin, end) and moves it to // the front. It's faster than sorting all the moves in advance when there // are few moves, e.g., the possible captures. - Move pick_best(ExtMove* begin, ExtMove* end) - { - std::swap(*begin, *std::max_element(begin, end)); - return *begin; + Move pick_best(ExtMove* begin, ExtMove* end) { + + std::swap(*begin, *std::max_element(begin, end)); + return *begin; } } // namespace @@ -73,6 +76,8 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Search::Stack* s) Square prevSq = to_sq((ss-1)->currentMove); countermove = pos.this_thread()->counterMoves[pos.piece_on(prevSq)][prevSq]; + killers[0] = ss->killers[0]; + killers[1] = ss->killers[1]; stage = pos.checkers() ? EVASION : MAIN_SEARCH; ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; @@ -111,11 +116,11 @@ MovePicker::MovePicker(const Position& p, Move ttm, Value th) stage = PROBCUT; - // In ProbCut we generate captures with SEE higher than the given threshold + // In ProbCut we generate captures with SEE higher than or equal to the given threshold ttMove = ttm && pos.pseudo_legal(ttm) && pos.capture(ttm) - && pos.see_ge(ttm, threshold + 1)? ttm : MOVE_NONE; + && pos.see_ge(ttm, threshold) ? ttm : MOVE_NONE; stage += (ttMove == MOVE_NONE); } @@ -141,27 +146,24 @@ template<> void MovePicker::score() { const HistoryStats& history = pos.this_thread()->history; - const FromToStats& fromTo = pos.this_thread()->fromTo; - const CounterMoveStats* cm = (ss-1)->counterMoves; - const CounterMoveStats* fm = (ss-2)->counterMoves; - const CounterMoveStats* f2 = (ss-4)->counterMoves; + const CounterMoveStats& cmh = *(ss-1)->counterMoves; + const CounterMoveStats& fmh = *(ss-2)->counterMoves; + const CounterMoveStats& fm2 = *(ss-4)->counterMoves; Color c = pos.side_to_move(); for (auto& m : *this) - m.value = history[pos.moved_piece(m)][to_sq(m)] - + (cm ? (*cm)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO) - + (fm ? (*fm)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO) - + (f2 ? (*f2)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO) - + fromTo.get(c, m); + m.value = cmh[pos.moved_piece(m)][to_sq(m)] + + fmh[pos.moved_piece(m)][to_sq(m)] + + fm2[pos.moved_piece(m)][to_sq(m)] + + history.get(c, m); } template<> void MovePicker::score() { - // Try captures ordered by MVV/LVA, then non-captures ordered by history value + // Try captures ordered by MVV/LVA, then non-captures ordered by stats heuristics const HistoryStats& history = pos.this_thread()->history; - const FromToStats& fromTo = pos.this_thread()->fromTo; Color c = pos.side_to_move(); for (auto& m : *this) @@ -169,7 +171,7 @@ void MovePicker::score() { m.value = PieceValue[MG][pos.piece_on(to_sq(m))] - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max; else - m.value = history[pos.moved_piece(m)][to_sq(m)] + fromTo.get(c, m); + m.value = history.get(c, m); } @@ -178,7 +180,7 @@ void MovePicker::score() { /// left. It picks the move with the biggest value from a list of generated moves /// taking care not to return the ttMove if it has already been searched. -Move MovePicker::next_move() { +Move MovePicker::next_move(bool skipQuiets) { Move move; @@ -210,7 +212,7 @@ Move MovePicker::next_move() { } ++stage; - move = ss->killers[0]; // First killer move + move = killers[0]; // First killer move if ( move != MOVE_NONE && move != ttMove && pos.pseudo_legal(move) @@ -219,7 +221,7 @@ Move MovePicker::next_move() { case KILLERS: ++stage; - move = ss->killers[1]; // Second killer move + move = killers[1]; // Second killer move if ( move != MOVE_NONE && move != ttMove && pos.pseudo_legal(move) @@ -231,8 +233,8 @@ Move MovePicker::next_move() { move = countermove; if ( move != MOVE_NONE && move != ttMove - && move != ss->killers[0] - && move != ss->killers[1] + && move != killers[0] + && move != killers[1] && pos.pseudo_legal(move) && !pos.capture(move)) return move; @@ -241,22 +243,18 @@ Move MovePicker::next_move() { cur = endBadCaptures; endMoves = generate(pos, cur); score(); - if (depth < 3 * ONE_PLY) - { - ExtMove* goodQuiet = std::partition(cur, endMoves, [](const ExtMove& m) - { return m.value > VALUE_ZERO; }); - insertion_sort(cur, goodQuiet); - } else - insertion_sort(cur, endMoves); + partial_insertion_sort(cur, endMoves, -4000 * depth / ONE_PLY); ++stage; case QUIET: - while (cur < endMoves) + while ( cur < endMoves + && (!skipQuiets || cur->value >= VALUE_ZERO)) { move = *cur++; + if ( move != ttMove - && move != ss->killers[0] - && move != ss->killers[1] + && move != killers[0] + && move != killers[1] && move != countermove) return move; } @@ -294,7 +292,7 @@ Move MovePicker::next_move() { { move = pick_best(cur++, endMoves); if ( move != ttMove - && pos.see_ge(move, threshold + 1)) + && pos.see_ge(move, threshold)) return move; } break;