X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=e0bd2a674025d0795955310c60758127509b4867;hp=ec36edfee5b278c859552c8e4b12f6a816f57b98;hb=333696318555004770f6d2acaae0eb743cc7e9de;hpb=13a73f67c018e58b2fd46f886c45ef2b75188c8e diff --git a/src/movepick.cpp b/src/movepick.cpp index ec36edfe..e0bd2a67 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, 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 @@ -30,7 +30,7 @@ namespace { EVASION, EVASIONS_S2, QSEARCH_0, CAPTURES_S3, QUIET_CHECKS_S3, QSEARCH_1, CAPTURES_S4, - PROBCUT, CAPTURES_S5, + MULTICUT, CAPTURES_S5, RECAPTURE, CAPTURES_S6, STOP }; @@ -50,7 +50,7 @@ namespace { } // Unary predicate used by std::partition to split positive scores from remaining - // ones so to sort separately the two sets, and with the second sort delayed. + // ones so as to sort the two sets separately, with the second sort delayed. inline bool has_positive_score(const ExtMove& ms) { return ms.score > 0; } // Picks the best move in the range (begin, end) and moves it to the front. @@ -65,19 +65,20 @@ namespace { /// Constructors of the MovePicker class. As arguments we pass information -/// to help it to return the presumably good moves first, to decide which +/// to help it to return the (presumably) good moves first, to decide which /// moves to return (in the quiescence search, for instance, we only want to -/// search captures, promotions and some checks) and about how important good -/// move ordering is at the current node. +/// search captures, promotions and some checks) and how important good move +/// ordering is at the current node. MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h, - Move* cm, Search::Stack* s) : pos(p), history(h), depth(d) { + Move* cm, Move* fm, Search::Stack* s) : pos(p), history(h), depth(d) { assert(d > DEPTH_ZERO); cur = end = moves; endBadCaptures = moves + MAX_MOVES - 1; countermoves = cm; + followupmoves = fm; ss = s; if (p.checkers()) @@ -127,9 +128,9 @@ MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, Piece assert(!pos.checkers()); - stage = PROBCUT; + stage = MULTICUT; - // In ProbCut we generate only captures that are better than the parent's + // In MultiCut we generate only captures that are better than the parent's // captured piece. captureThreshold = PieceValue[MG][pt]; ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE); @@ -209,10 +210,10 @@ void MovePicker::score() { } -/// generate_next() generates, scores and sorts the next bunch of moves, when -/// there are no more moves to try for the current phase. +/// generate_next_stage() generates, scores and sorts the next bunch of moves, +/// when there are no more moves to try for the current stage. -void MovePicker::generate_next() { +void MovePicker::generate_next_stage() { cur = moves; @@ -230,15 +231,24 @@ void MovePicker::generate_next() { killers[0].move = ss->killers[0]; killers[1].move = ss->killers[1]; killers[2].move = killers[3].move = MOVE_NONE; + killers[4].move = killers[5].move = MOVE_NONE; + + // Please note that following code is racy and could yield to rare (less + // than 1 out of a million) duplicated entries in SMP case. This is harmless. // Be sure countermoves are different from killers for (int i = 0; i < 2; ++i) - if (countermoves[i] != cur->move && countermoves[i] != (cur+1)->move) + if ( countermoves[i] != (cur+0)->move + && countermoves[i] != (cur+1)->move) (end++)->move = countermoves[i]; - if (countermoves[1] && countermoves[1] == countermoves[0]) // Due to SMP races - killers[3].move = MOVE_NONE; - + // Be sure followupmoves are different from killers and countermoves + for (int i = 0; i < 2; ++i) + if ( followupmoves[i] != (cur+0)->move + && followupmoves[i] != (cur+1)->move + && followupmoves[i] != (cur+2)->move + && followupmoves[i] != (cur+3)->move) + (end++)->move = followupmoves[i]; return; case QUIETS_1_S1: @@ -271,7 +281,7 @@ void MovePicker::generate_next() { end = generate(pos, moves); return; - case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: case RECAPTURE: + case EVASION: case QSEARCH_0: case QSEARCH_1: case MULTICUT: case RECAPTURE: stage = STOP; case STOP: end = cur + 1; // Avoid another next_phase() call @@ -284,9 +294,9 @@ void MovePicker::generate_next() { /// next_move() is the most important method of the MovePicker class. It returns -/// a new pseudo legal move every time is called, until there are no more moves +/// a new pseudo legal move every time it is called, until there are no more moves /// left. It picks the move with the biggest score from a list of generated moves -/// taking care not returning the ttMove if has already been searched previously. +/// taking care not to return the ttMove if it has already been searched. template<> Move MovePicker::next_move() { @@ -295,11 +305,11 @@ Move MovePicker::next_move() { while (true) { while (cur == end) - generate_next(); + generate_next_stage(); switch (stage) { - case MAIN_SEARCH: case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: + case MAIN_SEARCH: case EVASION: case QSEARCH_0: case QSEARCH_1: case MULTICUT: ++cur; return ttMove; @@ -330,7 +340,9 @@ Move MovePicker::next_move() { && move != killers[0].move && move != killers[1].move && move != killers[2].move - && move != killers[3].move) + && move != killers[3].move + && move != killers[4].move + && move != killers[5].move) return move; break;