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Unify scoring functions in MovePicker 

No functional change.
pull/1199/head
Joost VandeVondele 2017-08-09 14:04:59 +02:00 committed by Marco Costalba
parent b40e45c1cc
commit f731bcadb7
1 changed files with 16 additions and 34 deletions
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50
src/movepick.cpp
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@ -120,45 +120,27 @@ MovePicker::MovePicker(const Position& p, Move ttm, Value th)
stage += (ttMove == MOVE_NONE);
}
/// score() assigns 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, preferring
// captures near our home rank. Surprisingly, this appears to perform slightly
// better than SEE-based move ordering: exchanging big pieces before capturing
// a hanging piece probably helps to reduce the subtree size.
// In the main search we want to push captures with negative SEE values to the
// badCaptures[] array, but instead of doing it now we delay until the move
// has been picked up, saving some SEE calls in case we get a cutoff.
for (auto& m : *this)
m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
- Value(200 * relative_rank(pos.side_to_move(), to_sq(m)));
}
template<>
void MovePicker::score<QUIETS>() {
/// score() assigns a numerical value to each move in a list, used for sorting.
/// Captures are ordered by Most Valuable Victim (MVV), preferring captures
/// near our home rank. Quiets are ordered using the histories.
template<GenType T>
void MovePicker::score() {
for (auto& m : *this)
m.value = (*mainHistory)[pos.side_to_move()][from_to(m)]
+ (*contHistory[0])[pos.moved_piece(m)][to_sq(m)]
+ (*contHistory[1])[pos.moved_piece(m)][to_sq(m)]
+ (*contHistory[3])[pos.moved_piece(m)][to_sq(m)];
}
if (T == CAPTURES || (T == EVASIONS && pos.capture(m)))
m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
- (T == EVASIONS ? Value(type_of(pos.moved_piece(m)))
: Value(200 * relative_rank(pos.side_to_move(), to_sq(m))));
else if (T == QUIETS)
m.value = (*mainHistory)[pos.side_to_move()][from_to(m)]
+ (*contHistory[0])[pos.moved_piece(m)][to_sq(m)]
+ (*contHistory[1])[pos.moved_piece(m)][to_sq(m)]
+ (*contHistory[3])[pos.moved_piece(m)][to_sq(m)];
template<>
void MovePicker::score<EVASIONS>() {
// Try captures ordered by MVV/LVA, then non-captures ordered by stats heuristics
for (auto& m : *this)
if (pos.capture(m))
m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
- Value(type_of(pos.moved_piece(m))) + (1 << 28);
else
m.value = (*mainHistory)[pos.side_to_move()][from_to(m)];
else // Quiet evasions
m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] - (1 << 28);
}
/// 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 value from a list of generated moves