/*
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
}
}
- // 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.
- inline bool has_positive_score(const ExtMove& ms) { return ms.score > 0; }
+ // Unary predicate used by std::partition to split positive values from remaining
+ // ones so as to sort the two sets separately, with the second sort delayed.
+ inline bool has_positive_value(const ExtMove& ms) { return ms.value > 0; }
// Picks 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
std::swap(*begin, *std::max_element(begin, end));
return begin;
}
-}
+} // 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())
+ if (pos.checkers())
stage = EVASION;
else
}
MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
- Square sq) : pos(p), history(h), cur(moves), end(moves) {
+ Square s) : pos(p), history(h), cur(moves), end(moves) {
assert(d <= DEPTH_ZERO);
- if (p.checkers())
+ if (pos.checkers())
stage = EVASION;
else if (d > DEPTH_QS_NO_CHECKS)
else
{
stage = RECAPTURE;
- recaptureSquare = sq;
+ recaptureSquare = s;
ttm = MOVE_NONE;
}
}
-/// score() assign a numerical move ordering score to each move in a move list.
-/// The moves with highest scores will be picked first.
+/// score() assign a numerical value to each move in a move list. The moves with
+/// highest values will be picked first.
template<>
void MovePicker::score<CAPTURES>() {
// Winning and equal captures in the main search are ordered by MVV/LVA.
for (ExtMove* it = moves; it != end; ++it)
{
m = it->move;
- it->score = PieceValue[MG][pos.piece_on(to_sq(m))]
- - type_of(pos.moved_piece(m));
+ it->value = PieceValue[MG][pos.piece_on(to_sq(m))]
+ - Value(type_of(pos.moved_piece(m)));
- if (type_of(m) == PROMOTION)
- it->score += PieceValue[MG][promotion_type(m)] - PieceValue[MG][PAWN];
+ if (type_of(m) == ENPASSANT)
+ it->value += PieceValue[MG][PAWN];
- else if (type_of(m) == ENPASSANT)
- it->score += PieceValue[MG][PAWN];
+ else if (type_of(m) == PROMOTION)
+ it->value += PieceValue[MG][promotion_type(m)] - PieceValue[MG][PAWN];
}
}
for (ExtMove* it = moves; it != end; ++it)
{
m = it->move;
- it->score = history[pos.moved_piece(m)][to_sq(m)];
+ it->value = history[pos.moved_piece(m)][to_sq(m)];
}
}
void MovePicker::score<EVASIONS>() {
// Try good captures ordered by MVV/LVA, then non-captures if destination square
// is not under attack, ordered by history value, then bad-captures and quiet
- // moves with a negative SEE. This last group is ordered by the SEE score.
+ // moves with a negative SEE. This last group is ordered by the SEE value.
Move m;
- int seeScore;
+ Value see;
for (ExtMove* it = moves; it != end; ++it)
{
m = it->move;
- if ((seeScore = pos.see_sign(m)) < 0)
- it->score = seeScore - HistoryStats::Max; // At the bottom
+ if ((see = pos.see_sign(m)) < VALUE_ZERO)
+ it->value = see - HistoryStats::Max; // At the bottom
else if (pos.capture(m))
- it->score = PieceValue[MG][pos.piece_on(to_sq(m))]
- - type_of(pos.moved_piece(m)) + HistoryStats::Max;
+ it->value = PieceValue[MG][pos.piece_on(to_sq(m))]
+ - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max;
else
- it->score = history[pos.moved_piece(m)][to_sq(m)];
+ it->value = history[pos.moved_piece(m)][to_sq(m)];
}
}
-/// 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;
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:
endQuiets = end = generate<QUIETS>(pos, moves);
score<QUIETS>();
- end = std::partition(cur, end, has_positive_score);
+ end = std::partition(cur, end, has_positive_value);
insertion_sort(cur, end);
return;
case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: case RECAPTURE:
stage = STOP;
+ /* Fall through */
+
case STOP:
end = cur + 1; // Avoid another next_phase() call
return;
/// next_move() is the most important method of the MovePicker class. It returns
/// 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.
+/// 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.
template<>
Move MovePicker::next_move<false>() {
while (true)
{
while (cur == end)
- generate_next();
+ generate_next_stage();
switch (stage) {
move = pick_best(cur++, end)->move;
if (move != ttMove)
{
- if (pos.see_sign(move) >= 0)
+ if (pos.see_sign(move) >= VALUE_ZERO)
return move;
// Losing capture, move it to the tail of the array
case KILLERS_S1:
move = (cur++)->move;
if ( move != MOVE_NONE
- && pos.pseudo_legal(move)
&& move != ttMove
+ && pos.pseudo_legal(move)
&& !pos.capture(move))
return move;
break;
&& 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;
projects / stockfish / blobdiff