X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=2867e7664716ba32c6b5b0d90284a4e75f8ede15;hp=4b1fccc4fdc810db49cb461ec54d2502b5f4d716;hb=88885399f4a8bdc579c2b75cd892e78821631c63;hpb=2943e1ca3171341cd301b18280f3fa3b6bdda162

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 4b1fccc4..2867e766 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -1,17 +1,18 @@
 /*
-  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 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 <http://www.gnu.org/licenses/>.
 */
@@ -38,7 +39,7 @@ namespace {
 
   /// Variables
 
-  MovePicker::MovegenPhase PhaseTable[32];  
+  MovePicker::MovegenPhase PhaseTable[32];
   int MainSearchPhaseIndex;
   int EvasionsPhaseIndex;
   int QsearchWithChecksPhaseIndex;
@@ -61,7 +62,7 @@ namespace {
 /// move ordering is at the current node.
 
 MovePicker::MovePicker(const Position& p, bool pvnode, Move ttm, Move mk,
-                       Move k1, Move k2, Depth d) : pos(p) {  
+                       Move k1, Move k2, Depth d) : pos(p) {
   pvNode = pvnode;
   ttMove = ttm;
   mateKiller = (mk == ttm)? MOVE_NONE : mk;
@@ -73,11 +74,11 @@ MovePicker::MovePicker(const Position& p, bool pvnode, Move ttm, Move mk,
   numOfBadCaptures = 0;
   dc = p.discovered_check_candidates(p.side_to_move());
 
-  if(p.is_check())
+  if (p.is_check())
     phaseIndex = EvasionsPhaseIndex;
-  else if(depth > Depth(0))
+  else if (depth > Depth(0))
     phaseIndex = MainSearchPhaseIndex;
-  else if(depth == Depth(0))
+  else if (depth == Depth(0))
     phaseIndex = QsearchWithChecksPhaseIndex;
   else
     phaseIndex = QsearchWithoutChecksPhaseIndex;
@@ -99,7 +100,7 @@ Move MovePicker::get_next_move() {
   while (true)
   {
     // If we already have a list of generated moves, pick the best move from
-    // the list, and return it:
+    // the list, and return it.
     move = pick_move_from_list();
     if (move != MOVE_NONE)
     {
@@ -107,7 +108,7 @@ Move MovePicker::get_next_move() {
         return move;
     }
 
-    // Next phase:
+    // Next phase
     phaseIndex++;
     switch (PhaseTable[phaseIndex]) {
 
@@ -115,7 +116,7 @@ Move MovePicker::get_next_move() {
         if (ttMove != MOVE_NONE)
         {
             assert(move_is_ok(ttMove));
-            if (generate_move_if_legal(pos, ttMove, pinned) != MOVE_NONE)
+            if (move_is_legal(pos, ttMove, pinned))
                 return ttMove;
         }
         break;
@@ -124,12 +125,12 @@ Move MovePicker::get_next_move() {
         if (mateKiller != MOVE_NONE)
         {
             assert(move_is_ok(mateKiller));
-            if (generate_move_if_legal(pos, mateKiller, pinned) != MOVE_NONE)
-                return ttMove;
-        }
-        break;
+            if (move_is_legal(pos, mateKiller, pinned))
+                return mateKiller;
+       }
+       break;
 
-    case PH_GOOD_CAPTURES:      
+    case PH_GOOD_CAPTURES:
         numOfMoves = generate_captures(pos, moves);
         score_captures();
         movesPicked = 0;
@@ -146,13 +147,13 @@ Move MovePicker::get_next_move() {
         break;
 
     case PH_EVASIONS:
-        assert(pos.is_check());      
+        assert(pos.is_check());
         numOfMoves = generate_evasions(pos, moves);
         score_evasions();
         movesPicked = 0;
         break;
 
-    case PH_QCAPTURES:      
+    case PH_QCAPTURES:
         numOfMoves = generate_captures(pos, moves);
         score_qcaptures();
         movesPicked = 0;
@@ -171,9 +172,6 @@ Move MovePicker::get_next_move() {
         return MOVE_NONE;
     }
   }
-  assert(false);
-
-  return MOVE_NONE;
 }
 
 
@@ -182,25 +180,25 @@ Move MovePicker::get_next_move() {
 
 Move MovePicker::get_next_move(Lock &lock) {
 
-  lock_grab(&lock);
-  if (finished)
-  {
-      lock_release(&lock);
-      return MOVE_NONE;
-  }
-  Move m = get_next_move();
-  if (m == MOVE_NONE)
-      finished = true;
-
-  lock_release(&lock);   
-  return m;
+   lock_grab(&lock);
+   if (finished)
+   {
+       lock_release(&lock);
+       return MOVE_NONE;
+   }
+   Move m = get_next_move();
+   if (m == MOVE_NONE)
+       finished = true;
+
+   lock_release(&lock);
+   return m;
 }
 
+
 /// 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.
@@ -214,35 +212,42 @@ void MovePicker::score_captures() {
   // the subtree size.
   for (int i = 0; i < numOfMoves; i++)
   {
-      Move m = moves[i].move;
-      moves[i].score = pos.see(m);
-      if (moves[i].score >= 0)
+      int seeValue = pos.see(moves[i].move);
+      if (seeValue >= 0)
       {
-          moves[i].score = move_promotion(m) ? QueenValueMidgame
-                          : int(pos.midgame_value_of_piece_on(move_to(m)))
-                           -int(pos.type_of_piece_on(move_from(m)));
-          // FIXME second term seems wrong !
-      }
+          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;
   }
 }
 
 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);
-
-      // Ensure moves in history are always sorted as first
-      if (moves[i].score > 0)
-          moves[i].score += 1000;
-
-      moves[i].score += pos.mg_pst_delta(moves[i].move);
+  // 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.
+  Move m;
+  int hs;
+
+  for (int i = 0; i < numOfMoves; i++)
+  {
+      m = moves[i].move;
+
+      if (m == killer1)
+          hs = HistoryMax + 2;
+      else if (m == killer2)
+          hs = HistoryMax + 1;
+      else
+          hs = H.move_ordering_score(pos.piece_on(move_from(m)), m);
+
+      // Ensure moves in history are always sorted as first
+      if (hs > 0)
+          hs += 1000;
+
+      moves[i].score = hs + pos.mg_pst_delta(m);
   }
 }
 
@@ -255,11 +260,9 @@ void MovePicker::score_evasions() {
           moves[i].score = 2*HistoryMax;
       else if (!pos.square_is_empty(move_to(m)))
       {
-          moves[i].score = pos.see(m);
-          if (moves[i].score >= 0)
-              moves[i].score += HistoryMax;          
-      }
-      else
+          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);
   }
   // FIXME try psqt also here
@@ -267,18 +270,36 @@ void MovePicker::score_evasions() {
 
 void MovePicker::score_qcaptures() {
 
-  // Use MVV/LVA ordering.
+  // Use MVV/LVA ordering
   for (int i = 0; i < numOfMoves; i++)
   {
       Move m = moves[i].move;
-      moves[i].score = move_promotion(m) ? QueenValueMidgame
-                      : int(pos.midgame_value_of_piece_on(move_to(m)))
-                       -int(pos.midgame_value_of_piece_on(move_to(m))) / 64;
-      // FIXME Why second term like that ???
+      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;
   }
 }
 
 
+/// find_best_index() loops across the moves and returns index of
+/// the highest scored one.
+
+int MovePicker::find_best_index() {
+
+  int bestScore = -10000000, bestIndex = -1;
+
+  for (int i = movesPicked; i < numOfMoves; i++)
+      if (moves[i].score > bestScore)
+      {
+          bestIndex = i;
+          bestScore = moves[i].score;
+      }
+  return bestIndex;
+}
+
+
 /// MovePicker::pick_move_from_list() picks the move with the biggest score
 /// from a list of generated moves (moves[] or badCaptures[], depending on
 /// the current move generation phase).  It takes care not to return the
@@ -289,18 +310,17 @@ void MovePicker::score_qcaptures() {
 
 Move MovePicker::pick_move_from_list() {
 
-  int bestScore = -10000000;
   int bestIndex;
   Move move;
 
   switch (PhaseTable[phaseIndex]) {
-
   case PH_GOOD_CAPTURES:
       assert(!pos.is_check());
       assert(movesPicked >= 0);
+
       while (movesPicked < numOfMoves)
       {
-          bestScore = -10000000;
+          int bestScore = -10000000;
           bestIndex = -1;
           for (int i = movesPicked; i < numOfMoves; i++)
           {
@@ -310,20 +330,20 @@ Move MovePicker::pick_move_from_list() {
                   assert(numOfBadCaptures < 63);
                   badCaptures[numOfBadCaptures++] = moves[i];
                   moves[i--] = moves[--numOfMoves];
-               }
-               else if (moves[i].score > bestScore)
-               {
-                   bestIndex = i;
-                   bestScore = moves[i].score;
-               }
+              }
+              else if (moves[i].score > bestScore)
+              {
+                  bestIndex = i;
+                  bestScore = moves[i].score;
+              }
           }
           if (bestIndex != -1) // Found a good capture
           {
-              move = moves[bestIndex].move;
+              move = moves[bestIndex].move;
               moves[bestIndex] = moves[movesPicked++];
               if (   move != ttMove
                   && move != mateKiller
-                  && pos.move_is_legal(move, pinned))
+                  && pos.pl_move_is_legal(move, pinned))
                   return move;
           }
       }
@@ -332,59 +352,43 @@ Move MovePicker::pick_move_from_list() {
   case PH_NONCAPTURES:
       assert(!pos.is_check());
       assert(movesPicked >= 0);
+
       while (movesPicked < numOfMoves)
       {
           // 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)
-          {
-              bestScore = -10000000;
-              bestIndex = -1;
-              for (int i = movesPicked; i < numOfMoves; i++)
-                  if(moves[i].score > bestScore)
-                  {
-                      bestIndex = i;
-                      bestScore = moves[i].score;
-                  }
-          } else
-              bestIndex = movesPicked;
+          bestIndex = (pvNode || movesPicked < 12) ? find_best_index() : movesPicked;
 
           if (bestIndex != -1)
           {
-              move = moves[bestIndex].move;
+              move = moves[bestIndex].move;
               moves[bestIndex] = moves[movesPicked++];
               if (   move != ttMove
                   && move != mateKiller
-                  && pos.move_is_legal(move, pinned))
+                  && pos.pl_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;
-              }
+          bestIndex = find_best_index();
 
           if (bestIndex != -1)
           {
-              move = moves[bestIndex].move;
+              move = moves[bestIndex].move;
               moves[bestIndex] = moves[movesPicked++];
               return move;
           }
-      }
-      break;
+    }
+    break;
 
   case PH_BAD_CAPTURES:
       assert(!pos.is_check());
@@ -396,7 +400,7 @@ Move MovePicker::pick_move_from_list() {
           move = badCaptures[badCapturesPicked++].move;
           if (   move != ttMove
               && move != mateKiller
-              && pos.move_is_legal(move, pinned))
+              && pos.pl_move_is_legal(move, pinned))
               return move;
       }
       break;
@@ -406,27 +410,15 @@ Move MovePicker::pick_move_from_list() {
       assert(movesPicked >= 0);
       while (movesPicked < numOfMoves)
       {
-          bestScore = -10000000;
-          if (movesPicked < 4) // FIXME makes sens to score qcaps?
-          {
-              bestIndex = -1;
-              for (int i = movesPicked; i < numOfMoves; i++)
-                  if(moves[i].score > bestScore)
-                  {
-                      bestIndex = i;
-                      bestScore = moves[i].score;
-                  }
-          } else
-              bestIndex = movesPicked;
+          bestIndex = (movesPicked < 4 ? find_best_index() : movesPicked);
 
           if (bestIndex != -1)
           {
-              move = moves[bestIndex].move;
+              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?
-              // FIXME !!!
-              if (/* move != ttMove && */ pos.move_is_legal(move, pinned))
+              if (/* move != ttMove && */ pos.pl_move_is_legal(move, pinned))
                   return move;
           }
       }
@@ -441,8 +433,7 @@ Move MovePicker::pick_move_from_list() {
       {
           move = moves[movesPicked++].move;
           // Remember to change the line below if we decide to hash the qsearch!
-          // FIXME !!!
-          if (/* move != ttMove && */ pos.move_is_legal(move, pinned))
+          if (/* move != ttMove && */ pos.pl_move_is_legal(move, pinned))
               return move;
       }
       break;
@@ -458,13 +449,14 @@ Move MovePicker::pick_move_from_list() {
 /// picked next move. It can be used in search to further differentiate
 /// according to the current move type: capture, non capture, escape, etc.
 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
+/// and QsearchWithoutChecksPhaseIndex variables. It is only called once
 /// during program startup, and never again while the program is running.
 
 void MovePicker::init_phase_table() {