X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=c4eaa902e292e64cdea5858f4f9ae3318f07ec92;hp=b09647953a7fe50a6647d0c21668dcea340d20d6;hb=917944e9c5324cc9659e630570e1852270b22bd4;hpb=b84af67f4c88f3e3f7b61bf2035475f79fb3e62e

diff --git a/src/movepick.cpp b/src/movepick.cpp
index b0964795..c4eaa902 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) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2013 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
@@ -18,16 +18,14 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <algorithm>
 #include <cassert>
 
-#include "movegen.h"
 #include "movepick.h"
 #include "thread.h"
 
 namespace {
 
-  enum Sequencer {
+  enum Stages {
     MAIN_SEARCH, CAPTURES_S1, KILLERS_S1, QUIETS_1_S1, QUIETS_2_S1, BAD_CAPTURES_S1,
     EVASION,     EVASIONS_S2,
     QSEARCH_0,   CAPTURES_S3, QUIET_CHECKS_S3,
@@ -37,17 +35,31 @@ namespace {
     STOP
   };
 
+  // Our insertion sort, guaranteed to be stable, as is needed
+  void insertion_sort(ExtMove* begin, ExtMove* end)
+  {
+    ExtMove tmp, *p, *q;
+
+    for (p = begin + 1; p < end; ++p)
+    {
+        tmp = *p;
+        for (q = p; q != begin && *(q-1) < tmp; --q)
+            *q = *(q-1);
+        *q = tmp;
+    }
+  }
+
   // 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 MoveStack& move) { return move.score > 0; }
+  inline bool has_positive_score(const ExtMove& ms) { return ms.score > 0; }
 
-  // Picks and moves to the front the best move in the range [firstMove, lastMove),
+  // Picks and moves to the front the best move in the range [begin, end),
   // it is faster than sorting all the moves in advance when moves are few, as
   // normally are the possible captures.
-  inline MoveStack* pick_best(MoveStack* firstMove, MoveStack* lastMove)
+  inline ExtMove* pick_best(ExtMove* begin, ExtMove* end)
   {
-      std::swap(*firstMove, *std::max_element(firstMove, lastMove));
-      return firstMove;
+      std::swap(*begin, *std::max_element(begin, end));
+      return begin;
   }
 }
 
@@ -58,95 +70,89 @@ namespace {
 /// search captures, promotions and some checks) and about how important good
 /// move ordering is at the current node.
 
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
-                       Search::Stack* s, Value beta) : pos(p), H(h), depth(d) {
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
+                       Move* cm, Search::Stack* s) : pos(p), history(h), depth(d) {
 
   assert(d > DEPTH_ZERO);
 
-  captureThreshold = 0;
-  curMove = lastMove = moves;
-  lastBadCapture = moves + MAX_MOVES - 1;
+  cur = end = moves;
+  endBadCaptures = moves + MAX_MOVES - 1;
+  countermoves = cm;
   ss = s;
 
-  if (p.in_check())
-      phase = EVASION;
+  if (p.checkers())
+      stage = EVASION;
 
   else
-  {
-      phase = MAIN_SEARCH;
-
-      killers[0].move = ss->killers[0];
-      killers[1].move = ss->killers[1];
+      stage = MAIN_SEARCH;
 
-      // Consider sligtly negative captures as good if at low depth and far from beta
-      if (ss && ss->eval < beta - PawnValueMg && d < 3 * ONE_PLY)
-          captureThreshold = -PawnValueMg;
-
-      // Consider negative captures as good if still enough to reach beta
-      else if (ss && ss->eval > beta)
-          captureThreshold = beta - ss->eval;
-  }
-
-  ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
-  lastMove += (ttMove != MOVE_NONE);
+  ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE);
+  end += (ttMove != MOVE_NONE);
 }
 
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
-                       Square sq) : pos(p), H(h), curMove(moves), lastMove(moves) {
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
+                       Square sq) : pos(p), history(h), cur(moves), end(moves) {
 
   assert(d <= DEPTH_ZERO);
 
-  if (p.in_check())
-      phase = EVASION;
+  if (p.checkers())
+      stage = EVASION;
 
   else if (d > DEPTH_QS_NO_CHECKS)
-      phase = QSEARCH_0;
+      stage = QSEARCH_0;
 
   else if (d > DEPTH_QS_RECAPTURES)
   {
-      phase = QSEARCH_1;
+      stage = QSEARCH_1;
 
       // Skip TT move if is not a capture or a promotion, this avoids qsearch
       // tree explosion due to a possible perpetual check or similar rare cases
       // when TT table is full.
-      if (ttm && !pos.is_capture_or_promotion(ttm))
+      if (ttm && !pos.capture_or_promotion(ttm))
           ttm = MOVE_NONE;
   }
   else
   {
-      phase = RECAPTURE;
+      stage = RECAPTURE;
       recaptureSquare = sq;
       ttm = MOVE_NONE;
   }
 
-  ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
-  lastMove += (ttMove != MOVE_NONE);
+  ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE);
+  end += (ttMove != MOVE_NONE);
 }
 
-MovePicker::MovePicker(const Position& p, Move ttm, const History& h, PieceType pt)
-                       : pos(p), H(h), curMove(moves), lastMove(moves) {
+MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, PieceType pt)
+                       : pos(p), history(h), cur(moves), end(moves) {
 
-  assert(!pos.in_check());
+  assert(!pos.checkers());
 
-  phase = PROBCUT;
+  stage = PROBCUT;
 
   // In ProbCut we generate only captures better than parent's captured piece
-  captureThreshold = PieceValue[Mg][pt];
-  ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE);
+  captureThreshold = PieceValue[MG][pt];
+  ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE);
 
-  if (ttMove && (!pos.is_capture(ttMove) ||  pos.see(ttMove) <= captureThreshold))
+  if (ttMove && (!pos.capture(ttMove) || pos.see(ttMove) <= captureThreshold))
       ttMove = MOVE_NONE;
 
-  lastMove += (ttMove != MOVE_NONE);
+  end += (ttMove != MOVE_NONE);
 }
 
 
-/// MovePicker::score_captures(), MovePicker::score_noncaptures() and
-/// MovePicker::score_evasions() assign a numerical move ordering score
-/// to each move in a move list.  The moves with highest scores will be
-/// picked first by next_move().
+/// quiet_moves() returns a pointer to the beginning of moves array. It
+/// is used to access already tried quiet moves when updating history.
 
-void MovePicker::score_captures() {
+const ExtMove* MovePicker::quiet_moves() const {
+  return  stage == KILLERS_S1 ? killers
+        : stage == QUIETS_1_S1 || stage == QUIETS_2_S1 ? moves : NULL;
+}
+
+
+/// score() assign a numerical move ordering score to each move in a move list.
+/// The moves with highest scores will be picked first.
+template<>
+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
@@ -162,104 +168,121 @@ void MovePicker::score_captures() {
   // some SEE calls in case we get a cutoff (idea from Pablo Vazquez).
   Move m;
 
-  for (MoveStack* cur = moves; cur != lastMove; cur++)
+  for (ExtMove* it = moves; it != end; ++it)
   {
-      m = cur->move;
-      cur->score =  PieceValue[Mg][pos.piece_on(to_sq(m))]
-                  - type_of(pos.piece_moved(m));
+      m = it->move;
+      it->score =  PieceValue[MG][pos.piece_on(to_sq(m))]
+                 - type_of(pos.moved_piece(m));
 
       if (type_of(m) == PROMOTION)
-          cur->score += PieceValue[Mg][promotion_type(m)];
+          it->score += PieceValue[MG][promotion_type(m)] - PieceValue[MG][PAWN];
+
+      else if (type_of(m) == ENPASSANT)
+          it->score += PieceValue[MG][PAWN];
   }
 }
 
-void MovePicker::score_noncaptures() {
+template<>
+void MovePicker::score<QUIETS>() {
 
   Move m;
 
-  for (MoveStack* cur = moves; cur != lastMove; cur++)
+  for (ExtMove* it = moves; it != end; ++it)
   {
-      m = cur->move;
-      cur->score = H.value(pos.piece_moved(m), to_sq(m));
+      m = it->move;
+      it->score = history[pos.moved_piece(m)][to_sq(m)];
   }
 }
 
-void MovePicker::score_evasions() {
+template<>
+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.
   Move m;
   int seeScore;
 
-  if (lastMove < moves + 2)
-      return;
-
-  for (MoveStack* cur = moves; cur != lastMove; cur++)
+  for (ExtMove* it = moves; it != end; ++it)
   {
-      m = cur->move;
+      m = it->move;
       if ((seeScore = pos.see_sign(m)) < 0)
-          cur->score = seeScore - History::MaxValue; // Be sure we are at the bottom
-      else if (pos.is_capture(m))
-          cur->score =  PieceValue[Mg][pos.piece_on(to_sq(m))]
-                      - type_of(pos.piece_moved(m)) + History::MaxValue;
+          it->score = seeScore - 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;
       else
-          cur->score = H.value(pos.piece_moved(m), to_sq(m));
+          it->score = history[pos.moved_piece(m)][to_sq(m)];
   }
 }
 
 
-/// MovePicker::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() generates, scores and sorts the next bunch of moves, when
+/// there are no more moves to try for the current phase.
 
 void MovePicker::generate_next() {
 
-  curMove = moves;
+  cur = moves;
 
-  switch (++phase) {
+  switch (++stage) {
 
   case CAPTURES_S1: case CAPTURES_S3: case CAPTURES_S4: case CAPTURES_S5: case CAPTURES_S6:
-      lastMove = generate<CAPTURES>(pos, moves);
-      score_captures();
+      end = generate<CAPTURES>(pos, moves);
+      score<CAPTURES>();
       return;
 
   case KILLERS_S1:
-      curMove = killers;
-      lastMove = curMove + 2;
+      cur = killers;
+      end = cur + 2;
+
+      killers[0].move = ss->killers[0];
+      killers[1].move = ss->killers[1];
+      killers[2].move = killers[3].move = MOVE_NONE;
+
+      // Be sure countermoves are different from killers
+      for (int i = 0; i < 2; ++i)
+          if (countermoves[i] != cur->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;
+
       return;
 
   case QUIETS_1_S1:
-      lastQuiet = lastMove = generate<QUIETS>(pos, moves);
-      score_noncaptures();
-      lastMove = std::partition(curMove, lastMove, has_positive_score);
-      sort<MoveStack>(curMove, lastMove);
+      endQuiets = end = generate<QUIETS>(pos, moves);
+      score<QUIETS>();
+      end = std::partition(cur, end, has_positive_score);
+      insertion_sort(cur, end);
       return;
 
   case QUIETS_2_S1:
-      curMove = lastMove;
-      lastMove = lastQuiet;
+      cur = end;
+      end = endQuiets;
       if (depth >= 3 * ONE_PLY)
-          sort<MoveStack>(curMove, lastMove);
+          insertion_sort(cur, end);
       return;
 
   case BAD_CAPTURES_S1:
       // Just pick them in reverse order to get MVV/LVA ordering
-      curMove = moves + MAX_MOVES - 1;
-      lastMove = lastBadCapture;
+      cur = moves + MAX_MOVES - 1;
+      end = endBadCaptures;
       return;
 
   case EVASIONS_S2:
-      lastMove = generate<EVASIONS>(pos, moves);
-      score_evasions();
+      end = generate<EVASIONS>(pos, moves);
+      if (end > moves + 1)
+          score<EVASIONS>();
       return;
 
   case QUIET_CHECKS_S3:
-      lastMove = generate<QUIET_CHECKS>(pos, moves);
+      end = generate<QUIET_CHECKS>(pos, moves);
       return;
 
   case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: case RECAPTURE:
-      phase = STOP;
+      stage = STOP;
   case STOP:
-      lastMove = curMove + 1; // Avoid another next_phase() call
+      end = cur + 1; // Avoid another next_phase() call
       return;
 
   default:
@@ -268,11 +291,10 @@ void MovePicker::generate_next() {
 }
 
 
-/// MovePicker::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 to return the tt move if has already been
-/// searched previously.
+/// 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
+/// 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.
 template<>
 Move MovePicker::next_move<false>() {
 
@@ -280,69 +302,69 @@ Move MovePicker::next_move<false>() {
 
   while (true)
   {
-      while (curMove == lastMove)
+      while (cur == end)
           generate_next();
 
-      switch (phase) {
+      switch (stage) {
 
       case MAIN_SEARCH: case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT:
-          curMove++;
+          ++cur;
           return ttMove;
 
       case CAPTURES_S1:
-          move = pick_best(curMove++, lastMove)->move;
+          move = pick_best(cur++, end)->move;
           if (move != ttMove)
           {
-              assert(captureThreshold <= 0); // Otherwise we cannot use see_sign()
-
-              if (pos.see_sign(move) >= captureThreshold)
+              if (pos.see_sign(move) >= 0)
                   return move;
 
               // Losing capture, move it to the tail of the array
-              (lastBadCapture--)->move = move;
+              (endBadCaptures--)->move = move;
           }
           break;
 
       case KILLERS_S1:
-          move = (curMove++)->move;
+          move = (cur++)->move;
           if (    move != MOVE_NONE
-              &&  pos.is_pseudo_legal(move)
+              &&  pos.pseudo_legal(move)
               &&  move != ttMove
-              && !pos.is_capture(move))
+              && !pos.capture(move))
               return move;
           break;
 
       case QUIETS_1_S1: case QUIETS_2_S1:
-          move = (curMove++)->move;
+          move = (cur++)->move;
           if (   move != ttMove
               && move != killers[0].move
-              && move != killers[1].move)
+              && move != killers[1].move
+              && move != killers[2].move
+              && move != killers[3].move)
               return move;
           break;
 
       case BAD_CAPTURES_S1:
-          return (curMove--)->move;
+          return (cur--)->move;
 
       case EVASIONS_S2: case CAPTURES_S3: case CAPTURES_S4:
-          move = pick_best(curMove++, lastMove)->move;
+          move = pick_best(cur++, end)->move;
           if (move != ttMove)
               return move;
           break;
 
       case CAPTURES_S5:
-           move = pick_best(curMove++, lastMove)->move;
+           move = pick_best(cur++, end)->move;
            if (move != ttMove && pos.see(move) > captureThreshold)
                return move;
            break;
 
       case CAPTURES_S6:
-          move = pick_best(curMove++, lastMove)->move;
+          move = pick_best(cur++, end)->move;
           if (to_sq(move) == recaptureSquare)
               return move;
           break;
 
       case QUIET_CHECKS_S3:
-          move = (curMove++)->move;
+          move = (cur++)->move;
           if (move != ttMove)
               return move;
           break;
@@ -359,6 +381,6 @@ Move MovePicker::next_move<false>() {
 
 /// Version of next_move() to use at split point nodes where the move is grabbed
 /// from the split point's shared MovePicker object. This function is not thread
-/// safe so should be lock protected by the caller.
+/// safe so must be lock protected by the caller.
 template<>
-Move MovePicker::next_move<true>() { return ss->sp->mp->next_move<false>(); }
+Move MovePicker::next_move<true>() { return ss->splitPoint->movePicker->next_move<false>(); }