From f731bcadb7908f03c42e3d63fefe82552f09c926 Mon Sep 17 00:00:00 2001 From: Joost VandeVondele Date: Wed, 9 Aug 2017 14:04:59 +0200 Subject: [PATCH] Unify scoring functions in MovePicker No functional change. --- src/movepick.cpp | 52 ++++++++++++++++-------------------------------- 1 file changed, 17 insertions(+), 35 deletions(-) diff --git a/src/movepick.cpp b/src/movepick.cpp index 1f946ead..3b6ecbbf 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -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 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 +void MovePicker::score() { -/// 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() { - // 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))); + 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)]; + + else // Quiet evasions + m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] - (1 << 28); } -template<> -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)]; -} - -template<> -void MovePicker::score() { - // 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)]; -} - - /// 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 -- 2.39.2