X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=f50f16b03b2ac9fbfd5c2f20d875fce22f1067e1;hp=4d2d31167ea2db2641c582c545ba3c6c46b1a0fe;hb=f6d245291664e1a521b3810051365c48c82bac78;hpb=58c7a5c4775f7efa333bb2c921583ffba301f6b2
diff --git a/src/movepick.cpp b/src/movepick.cpp
index 4d2d3116..f50f16b0 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -1,17 +1,19 @@
/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+ Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+ Copyright (C) 2008-2009 Marco Costalba
- Glaurung is free software: you can redistribute it and/or modify
+ Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
- Glaurung is distributed in the hope that it will be useful,
+
+
+ Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-
+
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
@@ -21,9 +23,11 @@
//// Includes
////
+#include
#include
#include "history.h"
+#include "evaluate.h"
#include "movegen.h"
#include "movepick.h"
#include "search.h"
@@ -38,16 +42,14 @@ namespace {
/// Variables
- MovePicker::MovegenPhase PhaseTable[32];
- int MainSearchPhaseIndex;
- int EvasionsPhaseIndex;
- int QsearchWithChecksPhaseIndex;
- int QsearchWithoutChecksPhaseIndex;
-
+ CACHE_LINE_ALIGNMENT
+ const MovegenPhaseT MainSearchPhaseTable[] = { PH_STOP, PH_NULL_MOVE, PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP};
+ const MovegenPhaseT EvasionsPhaseTable[] = { PH_STOP, PH_EVASIONS, PH_STOP};
+ const MovegenPhaseT QsearchWithChecksPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP};
+ const MovegenPhaseT QsearchWithoutChecksPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_QCAPTURES, PH_STOP};
}
-
////
//// Functions
////
@@ -60,32 +62,33 @@ namespace {
/// search captures, promotions and some checks) and about how important good
/// move ordering is at the current node.
-MovePicker::MovePicker(Position &p, bool pvnode, Move ttm, Move mk,
- Move k1, Move k2, Depth dpth) {
- pos = &p;
- pvNode = pvnode;
- ttMove = ttm;
- mateKiller = (mk == ttm)? MOVE_NONE : mk;
- killer1 = k1;
- killer2 = k2;
- depth = dpth;
- movesPicked = 0;
- numOfMoves = 0;
- numOfBadCaptures = 0;
- dc = p.discovered_check_candidates(p.side_to_move());
-
- if(p.is_check())
- phaseIndex = EvasionsPhaseIndex;
- else if(depth > Depth(0))
- phaseIndex = MainSearchPhaseIndex;
- else if(depth == Depth(0))
- phaseIndex = QsearchWithChecksPhaseIndex;
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
+ const History& h, SearchStack* ss, bool useNullMove) : pos(p), H(h) {
+ ttMoves[0] = ttm;
+ if (ss)
+ {
+ ttMoves[1] = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller;
+ killers[0] = ss->killers[0];
+ killers[1] = ss->killers[1];
+ } else
+ ttMoves[1] = killers[0] = killers[1] = MOVE_NONE;
+
+ movesPicked = numOfMoves = numOfBadCaptures = 0;
+ finished = false;
+
+ if (p.is_check())
+ phasePtr = EvasionsPhaseTable;
+ else if (d > Depth(0))
+ phasePtr = MainSearchPhaseTable;
+ else if (d == Depth(0))
+ phasePtr = QsearchWithChecksPhaseTable;
else
- phaseIndex = QsearchWithoutChecksPhaseIndex;
+ phasePtr = QsearchWithoutChecksPhaseTable;
- pinned = p.pinned_pieces(p.side_to_move());
+ Color us = pos.side_to_move();
- finished = false;
+ dc = p.discovered_check_candidates(us);
+ pinned = p.pinned_pieces(us);
}
@@ -94,92 +97,85 @@ MovePicker::MovePicker(Position &p, bool pvnode, Move ttm, Move mk,
/// are no more moves left of the types we are interested in.
Move MovePicker::get_next_move() {
+
Move move;
- while(true) {
+ while (true)
+ {
// If we already have a list of generated moves, pick the best move from
- // the list, and return it:
- move = this->pick_move_from_list();
- if(move != MOVE_NONE) {
- assert(move_is_ok(move));
- return move;
+ // the list, and return it.
+ move = pick_move_from_list();
+ if (move != MOVE_NONE)
+ {
+ assert(move_is_ok(move));
+ return move;
}
- // Next phase:
- phaseIndex++;
- switch(PhaseTable[phaseIndex]) {
-
- case PH_TT_MOVE:
- if(ttMove != MOVE_NONE) {
- assert(move_is_ok(ttMove));
- Move m = generate_move_if_legal(*pos, ttMove, pinned);
- if(m != MOVE_NONE) {
- assert(m == ttMove);
- return m;
- }
- }
- break;
+ // Next phase
+ phasePtr++;
+ switch (*phasePtr) {
- case PH_MATE_KILLER:
- if(mateKiller != MOVE_NONE) {
- assert(move_is_ok(mateKiller));
- Move m = generate_move_if_legal(*pos, mateKiller, pinned);
- if(m != MOVE_NONE) {
- assert(m == mateKiller);
- return m;
- }
- }
- break;
+ case PH_NULL_MOVE:
+ break;
+
+ case PH_TT_MOVES:
+ movesPicked = 0; // This is used as index to ttMoves[]
+ break;
case PH_GOOD_CAPTURES:
- // pinned = pos->pinned_pieces(pos->side_to_move());
- numOfMoves = generate_captures(*pos, moves);
- this->score_captures();
- movesPicked = 0;
- break;
+ numOfMoves = generate_captures(pos, moves);
+ score_captures();
+ std::sort(moves, moves + numOfMoves);
+ movesPicked = 0;
+ break;
- case PH_BAD_CAPTURES:
- badCapturesPicked = 0;
- break;
+ case PH_KILLERS:
+ movesPicked = 0; // This is used as index to killers[]
+ break;
case PH_NONCAPTURES:
- numOfMoves = generate_noncaptures(*pos, moves);
- this->score_noncaptures();
- movesPicked = 0;
- break;
+ numOfMoves = generate_noncaptures(pos, moves);
+ score_noncaptures();
+ std::sort(moves, moves + numOfMoves);
+ movesPicked = 0;
+ break;
+
+ case PH_BAD_CAPTURES:
+ // Bad captures SEE value is already calculated so just sort them
+ // to get SEE move ordering.
+ std::sort(badCaptures, badCaptures + numOfBadCaptures);
+ movesPicked = 0;
+ break;
case PH_EVASIONS:
- assert(pos->is_check());
- // pinned = pos->pinned_pieces(pos->side_to_move());
- numOfMoves = generate_evasions(*pos, moves);
- this->score_evasions();
- movesPicked = 0;
- break;
+ assert(pos.is_check());
+ numOfMoves = generate_evasions(pos, moves, pinned);
+ score_evasions();
+ std::sort(moves, moves + numOfMoves);
+ movesPicked = 0;
+ break;
case PH_QCAPTURES:
- // pinned = pos->pinned_pieces(pos->side_to_move());
- numOfMoves = generate_captures(*pos, moves);
- this->score_qcaptures();
- movesPicked = 0;
- break;
+ numOfMoves = generate_captures(pos, moves);
+ score_captures();
+ std::sort(moves, moves + numOfMoves);
+ movesPicked = 0;
+ break;
case PH_QCHECKS:
- numOfMoves = generate_checks(*pos, moves, dc);
- movesPicked = 0;
- break;
+ // Perhaps we should order moves move here? FIXME
+ numOfMoves = generate_non_capture_checks(pos, moves, dc);
+ movesPicked = 0;
+ break;
case PH_STOP:
- return MOVE_NONE;
+ return MOVE_NONE;
default:
- assert(false);
- return MOVE_NONE;
+ assert(false);
+ return MOVE_NONE;
}
}
-
- assert(false);
-
- return MOVE_NONE;
}
@@ -187,100 +183,92 @@ Move MovePicker::get_next_move() {
/// prevent multiple threads from picking the same move at a split point.
Move MovePicker::get_next_move(Lock &lock) {
- Move m;
lock_grab(&lock);
- if(finished) {
- lock_release(&lock);
- return MOVE_NONE;
+ if (finished)
+ {
+ lock_release(&lock);
+ return MOVE_NONE;
}
- m = this->get_next_move();
- if(m == MOVE_NONE)
- finished = true;
+ Move m = get_next_move();
+ if (m == MOVE_NONE)
+ finished = true;
+
lock_release(&lock);
-
return m;
}
-
-/// MovePicker::number_of_moves() simply returns the numOfMoves member
-/// variable. It is intended to be used in positions where the side to move
-/// is in check, for detecting checkmates or situations where there is only
-/// a single reply to check.
-
-int MovePicker::number_of_moves() const {
- return numOfMoves;
-}
-
/// MovePicker::score_captures(), MovePicker::score_noncaptures(),
/// MovePicker::score_evasions() and MovePicker::score_qcaptures() assign a
/// numerical move ordering score to each move in a move list. The moves
-/// with highest scores will be picked first by
-/// MovePicker::pick_move_from_list().
+/// with highest scores will be picked first by pick_move_from_list().
void MovePicker::score_captures() {
// Winning and equal captures in the main search are ordered by MVV/LVA.
// Suprisingly, this appears to perform slightly better than SEE based
- // move ordering. The reason is probably that in a position with a winning
+ // move ordering. The reason is probably that in a position with a winning
// capture, capturing a more valuable (but sufficiently defended) piece
- // first usually doesn't hurt. The opponent will have to recapture, and
+ // first usually doesn't hurt. The opponent will have to recapture, and
// the hanging piece will still be hanging (except in the unusual cases
- // where it is possible to recapture with the hanging piece). Exchanging
+ // where it is possible to recapture with the hanging piece). Exchanging
// big pieces before capturing a hanging piece probably helps to reduce
// the subtree size.
- for(int i = 0; i < numOfMoves; i++) {
- int seeValue = pos->see(moves[i].move);
- if(seeValue >= 0) {
- if(move_promotion(moves[i].move))
- moves[i].score = QueenValueMidgame;
- else
- moves[i].score =
- int(pos->midgame_value_of_piece_on(move_to(moves[i].move))) -
- int(pos->type_of_piece_on(move_from(moves[i].move)));
- }
- else
- moves[i].score = seeValue;
-
+ // In main search we want to push captures with negative SEE values to
+ // badCaptures[] array, but instead of doing it now we delay till when
+ // the move has been picked up in pick_move_from_list(), this way we save
+ // some SEE calls in case we get a cutoff (idea from Pablo Vazquez).
+ Move m;
+
+ // Use MVV/LVA ordering
+ for (int i = 0; i < numOfMoves; i++)
+ {
+ m = moves[i].move;
+ if (move_is_promotion(m))
+ moves[i].score = QueenValueMidgame;
+ else
+ moves[i].score = int(pos.midgame_value_of_piece_on(move_to(m)))
+ -int(pos.type_of_piece_on(move_from(m)));
}
}
void MovePicker::score_noncaptures() {
- for(int i = 0; i < numOfMoves; i++) {
- Move m = moves[i].move;
- if(m == killer1)
- moves[i].score = HistoryMax + 2;
- else if(m == killer2)
- moves[i].score = HistoryMax + 1;
- else
- moves[i].score = H.move_ordering_score(pos->piece_on(move_from(m)), m);
+ // First score by history, when no history is available then use
+ // piece/square tables values. This seems to be better then a
+ // random choice when we don't have an history for any move.
+ Piece piece;
+ Square from, to;
+ int hs;
+
+ for (int i = 0; i < numOfMoves; i++)
+ {
+ from = move_from(moves[i].move);
+ to = move_to(moves[i].move);
+ piece = pos.piece_on(from);
+ hs = H.move_ordering_score(piece, to);
+
+ // Ensure history is always preferred to pst
+ if (hs > 0)
+ hs += 1000;
+
+ // pst based scoring
+ moves[i].score = hs + pos.pst_delta(piece, from, to);
}
}
void MovePicker::score_evasions() {
- for(int i = 0; i < numOfMoves; i++) {
- Move m = moves[i].move;
- if(m == ttMove)
- moves[i].score = 2*HistoryMax;
- else if(!pos->square_is_empty(move_to(m))) {
- int seeScore = pos->see(m);
- moves[i].score = (seeScore >= 0)? seeScore + HistoryMax : seeScore;
- }
- else
- moves[i].score = H.move_ordering_score(pos->piece_on(move_from(m)), m);
- }
-}
-void MovePicker::score_qcaptures() {
- // Use MVV/LVA ordering.
- for(int i = 0; i < numOfMoves; i++) {
- Move m = moves[i].move;
- if(move_promotion(m))
- moves[i].score = QueenValueMidgame;
- else
- moves[i].score =
- int(pos->midgame_value_of_piece_on(move_to(m))) -
- int(pos->midgame_value_of_piece_on(move_to(m))) / 64;
+ for (int i = 0; i < numOfMoves; i++)
+ {
+ Move m = moves[i].move;
+ if (m == ttMoves[0])
+ moves[i].score = 2*HistoryMax;
+ else if (!pos.square_is_empty(move_to(m)))
+ {
+ int seeScore = pos.see(m);
+ moves[i].score = (seeScore >= 0)? seeScore + HistoryMax : seeScore;
+ } else
+ moves[i].score = H.move_ordering_score(pos.piece_on(move_from(m)), move_to(m));
}
}
@@ -289,193 +277,95 @@ void MovePicker::score_qcaptures() {
/// from a list of generated moves (moves[] or badCaptures[], depending on
/// the current move generation phase). It takes care not to return the
/// transposition table move if that has already been serched previously.
-/// While picking captures in the PH_GOOD_CAPTURES phase (i.e. while picking
-/// non-losing captures in the main search), it moves all captures with
-/// negative SEE values to the badCaptures[] array.
Move MovePicker::pick_move_from_list() {
- int bestScore = -10000000;
- int bestIndex;
- Move move;
- switch(PhaseTable[phaseIndex]) {
+ assert(movesPicked >= 0);
+ assert(!pos.is_check() || *phasePtr == PH_EVASIONS || *phasePtr == PH_STOP);
+ assert( pos.is_check() || *phasePtr != PH_EVASIONS);
- case PH_GOOD_CAPTURES:
- assert(!pos->is_check());
- assert(movesPicked >= 0);
- while(movesPicked < numOfMoves) {
- bestScore = -10000000;
- bestIndex = -1;
- for(int i = movesPicked; i < numOfMoves; i++) {
- if(moves[i].score < 0) {
- // Losing capture, move it to the badCaptures[] array
- assert(numOfBadCaptures < 63);
- badCaptures[numOfBadCaptures++] = moves[i];
- moves[i--] = moves[--numOfMoves];
- }
- else if(moves[i].score > bestScore) {
- bestIndex = i;
- bestScore = moves[i].score;
+ switch (*phasePtr) {
+
+ case PH_TT_MOVES:
+ while (movesPicked < 2) {
+ Move move = ttMoves[movesPicked++];
+ if ( move != MOVE_NONE
+ && move_is_legal(pos, move, pinned))
+ return move;
}
- }
- if(bestIndex != -1) { // Found a good capture
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
- if(move != ttMove && move != mateKiller &&
- pos->move_is_legal(move, pinned))
- return move;
- }
- }
- break;
+ break;
- case PH_NONCAPTURES:
- assert(!pos->is_check());
- assert(movesPicked >= 0);
- while(movesPicked < numOfMoves) {
- bestScore = -10000000;
-
- // If this is a PV node or we have only picked a few moves, scan
- // the entire move list for the best move. If many moves have already
- // been searched and it is not a PV node, we are probably failing low
- // anyway, so we just pick the first move from the list.
- if(pvNode || movesPicked < 12) {
- bestIndex = -1;
- for(int i = movesPicked; i < numOfMoves; i++)
- if(moves[i].score > bestScore) {
- bestIndex = i;
- bestScore = moves[i].score;
+ case PH_GOOD_CAPTURES:
+ while (movesPicked < numOfMoves)
+ {
+ Move move = moves[movesPicked++].move;
+ if ( move != ttMoves[0]
+ && move != ttMoves[1]
+ && pos.pl_move_is_legal(move, pinned))
+ {
+ // Check for a non negative SEE now
+ int seeValue = pos.see_sign(move);
+ if (seeValue >= 0)
+ return move;
+
+ // Losing capture, move it to the badCaptures[] array, note
+ // that move has now been already checked for legality.
+ assert(numOfBadCaptures < 63);
+ badCaptures[numOfBadCaptures].move = move;
+ badCaptures[numOfBadCaptures++].score = seeValue;
}
}
- else
- bestIndex = movesPicked;
-
- if(bestIndex != -1) {
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
- if(move != ttMove && move != mateKiller &&
- pos->move_is_legal(move, pinned))
- return move;
- }
- }
- break;
+ break;
- case PH_EVASIONS:
- assert(pos->is_check());
- assert(movesPicked >= 0);
- while(movesPicked < numOfMoves) {
- bestScore = -10000000;
- bestIndex = -1;
- for(int i = movesPicked; i < numOfMoves; i++)
- if(moves[i].score > bestScore) {
- bestIndex = i;
- bestScore = moves[i].score;
+ case PH_KILLERS:
+ while (movesPicked < 2) {
+ Move move = killers[movesPicked++];
+ if ( move != MOVE_NONE
+ && move != ttMoves[0]
+ && move != ttMoves[1]
+ && move_is_legal(pos, move, pinned)
+ && !pos.move_is_capture(move))
+ return move;
}
+ break;
- if(bestIndex != -1) {
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
- return move;
+ case PH_NONCAPTURES:
+ while (movesPicked < numOfMoves)
+ {
+ Move move = moves[movesPicked++].move;
+ if ( move != ttMoves[0]
+ && move != ttMoves[1]
+ && move != killers[0]
+ && move != killers[1]
+ && pos.pl_move_is_legal(move, pinned))
+ return move;
}
- }
- break;
+ break;
+
+ case PH_EVASIONS:
+ if (movesPicked < numOfMoves)
+ return moves[movesPicked++].move;
+ break;
case PH_BAD_CAPTURES:
- assert(!pos->is_check());
- assert(badCapturesPicked >= 0);
- // It's probably a good idea to use SEE move ordering here, instead
- // of just picking the first move. FIXME
- while(badCapturesPicked < numOfBadCaptures) {
- move = badCaptures[badCapturesPicked++].move;
- if(move != ttMove && move != mateKiller &&
- pos->move_is_legal(move, pinned))
- return move;
- }
- break;
+ if (movesPicked < numOfBadCaptures)
+ return badCaptures[movesPicked++].move;
+ break;
case PH_QCAPTURES:
- assert(!pos->is_check());
- assert(movesPicked >= 0);
- while(movesPicked < numOfMoves) {
- bestScore = -10000000;
- if(movesPicked < 4) {
- bestIndex = -1;
- for(int i = movesPicked; i < numOfMoves; i++)
- if(moves[i].score > bestScore) {
- bestIndex = i;
- bestScore = moves[i].score;
- }
- }
- else
- bestIndex = movesPicked;
-
- if(bestIndex != -1) {
- move = moves[bestIndex].move;
- moves[bestIndex] = moves[movesPicked++];
- // Remember to change the line below if we decide to hash the qsearch!
- // Maybe also postpone the legality check until after futility pruning?
- if(/* move != ttMove && */ pos->move_is_legal(move, pinned))
- return move;
- }
- }
- break;
-
case PH_QCHECKS:
- assert(!pos->is_check());
- assert(movesPicked >= 0);
- // Perhaps we should do something better than just picking the first
- // move here? FIXME
- while(movesPicked < numOfMoves) {
- move = moves[movesPicked++].move;
- // Remember to change the line below if we decide to hash the qsearch!
- if(/* move != ttMove && */ pos->move_is_legal(move, pinned))
- return move;
- }
- break;
+ while (movesPicked < numOfMoves)
+ {
+ Move move = moves[movesPicked++].move;
+ // Maybe postpone the legality check until after futility pruning?
+ if ( move != ttMoves[0]
+ && pos.pl_move_is_legal(move, pinned))
+ return move;
+ }
+ break;
default:
- break;
+ break;
}
-
return MOVE_NONE;
}
-
-MovePicker::MovegenPhase MovePicker::current_move_type() const {
- return PhaseTable[phaseIndex];
-}
-
-/// MovePicker::init_phase_table() initializes the PhaseTable[],
-/// MainSearchPhaseIndex, EvasionPhaseIndex, QsearchWithChecksPhaseIndex
-/// and QsearchWithoutChecksPhaseIndex variables. It is only called once
-/// during program startup, and never again while the program is running.
-
-void MovePicker::init_phase_table() {
- int i = 0;
-
- // Main search
- MainSearchPhaseIndex = i - 1;
- PhaseTable[i++] = PH_TT_MOVE;
- PhaseTable[i++] = PH_MATE_KILLER;
- PhaseTable[i++] = PH_GOOD_CAPTURES;
- // PH_KILLER_1 and PH_KILLER_2 are not yet used.
- // PhaseTable[i++] = PH_KILLER_1;
- // PhaseTable[i++] = PH_KILLER_2;
- PhaseTable[i++] = PH_NONCAPTURES;
- PhaseTable[i++] = PH_BAD_CAPTURES;
- PhaseTable[i++] = PH_STOP;
-
- // Check evasions
- EvasionsPhaseIndex = i - 1;
- PhaseTable[i++] = PH_EVASIONS;
- PhaseTable[i++] = PH_STOP;
-
- // Quiescence search with checks
- QsearchWithChecksPhaseIndex = i - 1;
- PhaseTable[i++] = PH_QCAPTURES;
- PhaseTable[i++] = PH_QCHECKS;
- PhaseTable[i++] = PH_STOP;
-
- // Quiescence search without checks
- QsearchWithoutChecksPhaseIndex = i - 1;
- PhaseTable[i++] = PH_QCAPTURES;
- PhaseTable[i++] = PH_STOP;
-}