X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=59b134532e4ec5318884c9b2810d902d0af337cb;hp=68f03a30ae0415803498305d0bdf880c0b6d7727;hb=683e6dc6566719f8737fad9bc30580bb0b4d8d20;hpb=a5c1b3e8f68a9c98e6be1f90e7d0295d05c685de

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 68f03a30..59b13453 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -8,6 +8,7 @@
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
+
   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
@@ -25,6 +26,7 @@
 #include <cassert>
 
 #include "history.h"
+#include "evaluate.h"
 #include "movegen.h"
 #include "movepick.h"
 #include "search.h"
@@ -43,7 +45,9 @@ namespace {
   int MainSearchPhaseIndex;
   int EvasionsPhaseIndex;
   int QsearchWithChecksPhaseIndex;
+  int QsearchNoCapturesPhaseIndex;
   int QsearchWithoutChecksPhaseIndex;
+  int NoMovesPhaseIndex;
 
 }
 
@@ -61,29 +65,36 @@ namespace {
 /// search captures, promotions and some checks) and about how important good
 /// 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) {
-  pvNode = pvnode;
+MovePicker::MovePicker(const Position& p, bool pv, Move ttm,
+                       const SearchStack& ss, Depth d, EvalInfo* ei) : pos(p) {
+  pvNode = pv;
   ttMove = ttm;
-  mateKiller = (mk == ttm)? MOVE_NONE : mk;
-  killer1 = k1;
-  killer2 = k2;
+  mateKiller = (ss.mateKiller == ttm)? MOVE_NONE : ss.mateKiller;
+  killer1 = ss.killers[0];
+  killer2 = ss.killers[1];
   depth = d;
   movesPicked = 0;
   numOfMoves = 0;
   numOfBadCaptures = 0;
-  dc = p.discovered_check_candidates(p.side_to_move());
+
+  // With EvalInfo we are able to know how many captures are possible before
+  // generating them. So avoid generating in case we know are zero.
+  Color us = pos.side_to_move();
+  Color them = opposite_color(us);
+  bool noCaptures =    ei
+                   && (ei->attackedBy[us][0] & pos.pieces_of_color(them)) == 0
+                   && !ei->mi->specialized_eval_exists()
+                   && (pos.ep_square() == SQ_NONE)
+                   && !pos.has_pawn_on_7th(us);
 
   if (p.is_check())
-    phaseIndex = EvasionsPhaseIndex;
+      phaseIndex = EvasionsPhaseIndex;
   else if (depth > Depth(0))
-    phaseIndex = MainSearchPhaseIndex;
+      phaseIndex = MainSearchPhaseIndex;
   else if (depth == Depth(0))
-    phaseIndex = QsearchWithChecksPhaseIndex;
+      phaseIndex = (noCaptures ? QsearchNoCapturesPhaseIndex : QsearchWithChecksPhaseIndex);
   else
-    phaseIndex = QsearchWithoutChecksPhaseIndex;
-
-  pinned = p.pinned_pieces(p.side_to_move());
+      phaseIndex = (noCaptures ? NoMovesPhaseIndex : QsearchWithoutChecksPhaseIndex);
 
   finished = false;
 }
@@ -116,7 +127,7 @@ Move MovePicker::get_next_move() {
         if (ttMove != MOVE_NONE)
         {
             assert(move_is_ok(ttMove));
-            if (move_is_legal(pos, ttMove, pinned))
+            if (move_is_legal(pos, ttMove))
                 return ttMove;
         }
         break;
@@ -125,7 +136,7 @@ Move MovePicker::get_next_move() {
         if (mateKiller != MOVE_NONE)
         {
             assert(move_is_ok(mateKiller));
-            if (move_is_legal(pos, mateKiller, pinned))
+            if (move_is_legal(pos, mateKiller))
                 return mateKiller;
        }
        break;
@@ -137,7 +148,7 @@ Move MovePicker::get_next_move() {
         break;
 
     case PH_BAD_CAPTURES:
-        badCapturesPicked = 0;
+        movesPicked = 0;
         break;
 
     case PH_NONCAPTURES:
@@ -160,7 +171,7 @@ Move MovePicker::get_next_move() {
         break;
 
     case PH_QCHECKS:
-        numOfMoves = generate_checks(pos, moves, dc);
+        numOfMoves = generate_checks(pos, moves);
         movesPicked = 0;
         break;
 
@@ -207,35 +218,61 @@ void MovePicker::score_captures() {
   // capture, capturing a more valuable (but sufficiently defended) piece
   // 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.
+  // While scoring captures it moves all captures with negative SEE values
+  // to the badCaptures[] array.
+  Move m;
+  int seeValue;
+
   for (int i = 0; i < numOfMoves; i++)
   {
-      int seeValue = pos.see(moves[i].move);
+      m = moves[i].move;
+      seeValue = pos.see(m);
       if (seeValue >= 0)
       {
-          if (move_promotion(moves[i].move))
+          if (move_promotion(m))
               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 = int(pos.midgame_value_of_piece_on(move_to(m)))
+                              -int(pos.type_of_piece_on(move_from(m)));
+      }
+      else
+      {
+          // Losing capture, move it to the badCaptures[] array
+          assert(numOfBadCaptures < 63);
           moves[i].score = seeValue;
+          badCaptures[numOfBadCaptures++] = moves[i];
+          moves[i--] = moves[--numOfMoves];
+      }
   }
 }
 
 void MovePicker::score_noncaptures() {
+  // 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++)
   {
-      Move m = moves[i].move;
+      m = moves[i].move;
+
       if (m == killer1)
-          moves[i].score = HistoryMax + 2;
+          hs = HistoryMax + 2;
       else if (m == killer2)
-          moves[i].score = HistoryMax + 1;
+          hs = HistoryMax + 1;
       else
-         moves[i].score = H.move_ordering_score(pos.piece_on(move_from(m)), m);
+          hs = H.move_ordering_score(pos.piece_on(move_from(m)), m);
+
+      // Ensure history is always preferred to pst
+      if (hs > 0)
+          hs += 1000;
+
+      // pst based scoring
+      moves[i].score = hs + pos.mg_pst_delta(m);
   }
 }
 
@@ -253,7 +290,6 @@ void MovePicker::score_evasions() {
       } else
           moves[i].score = H.move_ordering_score(pos.piece_on(move_from(m)), m);
   }
-  // FIXME try psqt also here
 }
 
 void MovePicker::score_qcaptures() {
@@ -266,19 +302,24 @@ void MovePicker::score_qcaptures() {
           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;
+                          -int(pos.type_of_piece_on(move_from(m)));
   }
 }
 
 
 /// find_best_index() loops across the moves and returns index of
-/// the highest scored one.
+/// the highest scored one. There is also a second version that
+/// lowers the priority of moves that attack the same square,
+/// so that if the best move that attack a square fails the next
+/// move picked attacks a different square if any, not the same one.
 
 int MovePicker::find_best_index() {
 
-  int bestScore = -10000000, bestIndex = -1;
+  assert(movesPicked < numOfMoves);
 
-  for (int i = movesPicked; i < numOfMoves; i++)
+  int bestIndex = movesPicked, bestScore = moves[movesPicked].score;
+
+  for (int i = movesPicked + 1; i < numOfMoves; i++)
       if (moves[i].score > bestScore)
       {
           bestIndex = i;
@@ -287,14 +328,50 @@ int MovePicker::find_best_index() {
   return bestIndex;
 }
 
+int MovePicker::find_best_index(Bitboard* squares, int values[]) {
+
+  assert(movesPicked < numOfMoves);
+
+  int hs;
+  Move m;
+  Square to;
+  int bestScore = -10000000, bestIndex = -1;
+
+  for (int i = movesPicked; i < numOfMoves; i++)
+  {
+      m = moves[i].move;
+      to = move_to(m);
+
+      if (!bit_is_set(*squares, to))
+      {
+          // Init at first use
+          set_bit(squares, to);
+          values[to] = 0;
+      }
+
+      hs = moves[i].score - values[to];
+      if (hs > bestScore)
+      {
+          bestIndex = i;
+          bestScore = hs;
+      }
+  }
+
+  if (bestIndex != -1)
+  {
+      // Raise value of the picked square, so next attack
+      // to the same square will get low priority.
+      to = move_to(moves[bestIndex].move);
+      values[to] += 0xB00;
+  }
+  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
 /// 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() {
 
@@ -302,38 +379,20 @@ Move MovePicker::pick_move_from_list() {
   Move move;
 
   switch (PhaseTable[phaseIndex]) {
+
   case PH_GOOD_CAPTURES:
       assert(!pos.is_check());
       assert(movesPicked >= 0);
 
       while (movesPicked < numOfMoves)
       {
-          int 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;
-              }
-          }
-          if (bestIndex != -1) // Found a good capture
-          {
-              move = moves[bestIndex].move;
-              moves[bestIndex] = moves[movesPicked++];
-              if (   move != ttMove
-                  && move != mateKiller
-                  && pos.pl_move_is_legal(move, pinned))
-                  return move;
-          }
+          bestIndex = find_best_index();
+          move = moves[bestIndex].move;
+          moves[bestIndex] = moves[movesPicked++];
+          if (   move != ttMove
+              && move != mateKiller
+              && pos.pl_move_is_legal(move))
+              return move;
       }
       break;
 
@@ -348,16 +407,12 @@ Move MovePicker::pick_move_from_list() {
           // 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.
           bestIndex = (pvNode || movesPicked < 12) ? find_best_index() : movesPicked;
-
-          if (bestIndex != -1)
-          {
-              move = moves[bestIndex].move;
-              moves[bestIndex] = moves[movesPicked++];
-              if (   move != ttMove
-                  && move != mateKiller
-                  && pos.pl_move_is_legal(move, pinned))
-                  return move;
-          }
+          move = moves[bestIndex].move;
+          moves[bestIndex] = moves[movesPicked++];
+          if (   move != ttMove
+              && move != mateKiller
+              && pos.pl_move_is_legal(move))
+              return move;
       }
       break;
 
@@ -368,27 +423,23 @@ Move MovePicker::pick_move_from_list() {
       while (movesPicked < numOfMoves)
       {
           bestIndex = find_best_index();
-
-          if (bestIndex != -1)
-          {
-              move = moves[bestIndex].move;
-              moves[bestIndex] = moves[movesPicked++];
-              return move;
-          }
+          move = moves[bestIndex].move;
+          moves[bestIndex] = moves[movesPicked++];
+          return move;
     }
     break;
 
   case PH_BAD_CAPTURES:
       assert(!pos.is_check());
-      assert(badCapturesPicked >= 0);
+      assert(movesPicked >= 0);
       // It's probably a good idea to use SEE move ordering here, instead
       // of just picking the first move.  FIXME
-      while (badCapturesPicked < numOfBadCaptures)
+      while (movesPicked < numOfBadCaptures)
       {
-          move = badCaptures[badCapturesPicked++].move;
+          move = badCaptures[movesPicked++].move;
           if (   move != ttMove
               && move != mateKiller
-              && pos.pl_move_is_legal(move, pinned))
+              && pos.pl_move_is_legal(move))
               return move;
       }
       break;
@@ -399,16 +450,12 @@ Move MovePicker::pick_move_from_list() {
       while (movesPicked < numOfMoves)
       {
           bestIndex = (movesPicked < 4 ? find_best_index() : 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.pl_move_is_legal(move, pinned))
-                  return 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?
+          if (/* move != ttMove && */ pos.pl_move_is_legal(move))
+              return move;
       }
       break;
 
@@ -421,7 +468,7 @@ Move MovePicker::pick_move_from_list() {
       {
           move = moves[movesPicked++].move;
           // Remember to change the line below if we decide to hash the qsearch!
-          if (/* move != ttMove && */ pos.pl_move_is_legal(move, pinned))
+          if (/* move != ttMove && */ pos.pl_move_is_legal(move))
               return move;
       }
       break;
@@ -444,8 +491,9 @@ MovePicker::MovegenPhase MovePicker::current_move_type() const {
 
 /// 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.
+/// QsearchNoCapturesPhaseIndex, QsearchWithoutChecksPhaseIndex and
+/// NoMovesPhaseIndex variables. It is only called once during program
+/// startup, and never again while the program is running.
 
 void MovePicker::init_phase_table() {
 
@@ -474,8 +522,17 @@ void MovePicker::init_phase_table() {
   PhaseTable[i++] = PH_QCHECKS;
   PhaseTable[i++] = PH_STOP;
 
+  // Quiescence search with checks only and no captures
+  QsearchNoCapturesPhaseIndex = i - 1;
+  PhaseTable[i++] = PH_QCHECKS;
+  PhaseTable[i++] = PH_STOP;
+
   // Quiescence search without checks
   QsearchWithoutChecksPhaseIndex = i - 1;
   PhaseTable[i++] = PH_QCAPTURES;
   PhaseTable[i++] = PH_STOP;
+
+  // Do not generate any move
+  NoMovesPhaseIndex = i - 1;
+  PhaseTable[i++] = PH_STOP;
 }