X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=7e338dbf62de586ec2e14fa0346eaab44c36b875;hp=4eb842a0e3e7d9eda96a7bf1e7a1ff1c599bb013;hb=b088f0aefd658261e9231b556382acf532920513;hpb=941f4e1643edbdf28118a47d0277747bb358d3ad

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 4eb842a0..7e338dbf 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 Marco Costalba
+  Copyright (C) 2008-2009 Marco Costalba
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -23,6 +23,7 @@
 //// Includes
 ////
 
+#include <algorithm>
 #include <cassert>
 
 #include "history.h"
@@ -41,16 +42,16 @@ 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 MainSearchNoNullPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP};
+  const MovegenPhaseT LowSearchPhaseTable[]  = { PH_STOP, PH_TT_MOVES, PH_GOOD_CAPTURES, PH_NULL_MOVE, 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
 ////
@@ -63,33 +64,35 @@ 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 pv, Move ttm,
-                       const SearchStack& ss, Depth d) : pos(p) {
-  pvNode = pv;
-  ttMove = ttm;
-  mateKiller = (ss.mateKiller == ttm)? MOVE_NONE : ss.mateKiller;
-  killer1 = ss.killers[0];
-  killer2 = ss.killers[1];
-  depth = d;
-  movesPicked = 0;
-  numOfMoves = 0;
-  numOfBadCaptures = 0;
+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())
-      phaseIndex = EvasionsPhaseIndex;
-  else if (depth > Depth(0))
-      phaseIndex = MainSearchPhaseIndex;
-  else if (depth == Depth(0))
-      phaseIndex = QsearchWithChecksPhaseIndex;
+      phasePtr = EvasionsPhaseTable;
+  else if (d >= Depth(3 * OnePly))
+      phasePtr = useNullMove ? MainSearchPhaseTable : MainSearchNoNullPhaseTable;
+  else if (d > Depth(0))
+      phasePtr = useNullMove ? LowSearchPhaseTable : MainSearchNoNullPhaseTable;
+  else if (d == Depth(0))
+      phasePtr = QsearchWithChecksPhaseTable;
   else
-      phaseIndex = QsearchWithoutChecksPhaseIndex;
+      phasePtr = QsearchWithoutChecksPhaseTable;
 
   Color us = pos.side_to_move();
 
   dc = p.discovered_check_candidates(us);
   pinned = p.pinned_pieces(us);
-
-  finished = false;
 }
 
 
@@ -113,40 +116,38 @@ Move MovePicker::get_next_move() {
     }
 
     // Next phase
-    phaseIndex++;
-    switch (PhaseTable[phaseIndex]) {
-
-    case PH_TT_MOVE:
-        if (ttMove != MOVE_NONE)
-        {
-            assert(move_is_ok(ttMove));
-            if (move_is_legal(pos, ttMove, pinned))
-                return ttMove;
-        }
-        break;
+    phasePtr++;
+    switch (*phasePtr) {
 
-    case PH_MATE_KILLER:
-        if (mateKiller != MOVE_NONE)
-        {
-            assert(move_is_ok(mateKiller));
-            if (move_is_legal(pos, mateKiller, pinned))
-                return mateKiller;
-        }
+    case PH_NULL_MOVE:
+        return MOVE_NULL;
+
+    case PH_TT_MOVES:
+        movesPicked = 0; // This is used as index to ttMoves[]
         break;
 
     case PH_GOOD_CAPTURES:
         numOfMoves = generate_captures(pos, moves);
         score_captures();
+        std::sort(moves, moves + numOfMoves);
         movesPicked = 0;
         break;
 
-    case PH_BAD_CAPTURES:
-        movesPicked = 0;
+    case PH_KILLERS:
+        movesPicked = 0; // This is used as index to killers[]
         break;
 
     case PH_NONCAPTURES:
         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;
 
@@ -154,17 +155,20 @@ Move MovePicker::get_next_move() {
         assert(pos.is_check());
         numOfMoves = generate_evasions(pos, moves, pinned);
         score_evasions();
+        std::sort(moves, moves + numOfMoves);
         movesPicked = 0;
         break;
 
     case PH_QCAPTURES:
         numOfMoves = generate_captures(pos, moves);
-        score_qcaptures();
+        score_captures();
+        std::sort(moves, moves + numOfMoves);
         movesPicked = 0;
         break;
 
     case PH_QCHECKS:
-        numOfMoves = generate_checks(pos, moves, dc);
+        // Perhaps we should order moves move here?  FIXME
+        numOfMoves = generate_non_capture_checks(pos, moves, dc);
         movesPicked = 0;
         break;
 
@@ -207,38 +211,28 @@ Move MovePicker::get_next_move(Lock &lock) {
 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
   // 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.
+  // 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;
-  int seeValue;
 
+  // Use MVV/LVA ordering
   for (int i = 0; i < numOfMoves; i++)
   {
       m = moves[i].move;
-      seeValue = pos.see(m);
-      if (seeValue >= 0)
-      {
-          if (move_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)));
-      }
+      if (move_is_promotion(m))
+          moves[i].score = QueenValueMidgame;
       else
-      {
-          // Losing capture, move it to the badCaptures[] array
-          assert(numOfBadCaptures < 63);
-          moves[i].score = seeValue;
-          badCaptures[numOfBadCaptures++] = moves[i];
-          moves[i--] = moves[--numOfMoves];
-      }
+          moves[i].score = int(pos.midgame_value_of_piece_on(move_to(m)))
+                          -int(pos.type_of_piece_on(move_from(m)));
   }
 }
 
@@ -246,26 +240,23 @@ 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;
+  Piece piece;
+  Square from, to;
   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);
+      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.mg_pst_delta(m);
+      moves[i].score = hs + pos.pst_delta<Position::MidGame>(piece, from, to);
   }
 }
 
@@ -274,90 +265,15 @@ void MovePicker::score_evasions() {
   for (int i = 0; i < numOfMoves; i++)
   {
       Move m = moves[i].move;
-      if (m == ttMove)
+      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)), 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.type_of_piece_on(move_from(m)));
-  }
-}
-
-
-/// find_best_index() loops across the moves and returns index of
-/// 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() {
-
-  assert(movesPicked < numOfMoves);
-
-  int bestIndex = movesPicked, bestScore = moves[movesPicked].score;
-
-  for (int i = movesPicked + 1; i < numOfMoves; i++)
-      if (moves[i].score > bestScore)
-      {
-          bestIndex = i;
-          bestScore = moves[i].score;
-      }
-  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;
-      }
+          moves[i].score = H.move_ordering_score(pos.piece_on(move_from(m)), move_to(m));
   }
-
-  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;
 }
 
 
@@ -368,100 +284,86 @@ int MovePicker::find_best_index(Bitboard* squares, int values[]) {
 
 Move MovePicker::pick_move_from_list() {
 
-  int bestIndex;
-  Move move;
+  assert(movesPicked >= 0);
+  assert(!pos.is_check() || *phasePtr == PH_EVASIONS || *phasePtr == PH_STOP);
+  assert( pos.is_check() || *phasePtr != PH_EVASIONS);
 
-  switch (PhaseTable[phaseIndex]) {
+  switch (*phasePtr) {
 
-  case PH_GOOD_CAPTURES:
-      assert(!pos.is_check());
-      assert(movesPicked >= 0);
+  case PH_TT_MOVES:
+        while (movesPicked < 2) {
+            Move move = ttMoves[movesPicked++];
+            if (   move != MOVE_NONE
+                && move_is_legal(pos, move, pinned))
+                return move;
+        }
+        break;
 
+  case PH_GOOD_CAPTURES:
       while (movesPicked < numOfMoves)
       {
-          bestIndex = find_best_index();
-          move = moves[bestIndex].move;
-          moves[bestIndex] = moves[movesPicked++];
-          if (   move != ttMove
-              && move != mateKiller
+          Move move = moves[movesPicked++].move;
+          if (   move != ttMoves[0]
+              && move != ttMoves[1]
               && pos.pl_move_is_legal(move, pinned))
-              return move;
+          {
+              // 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;
+          }
       }
       break;
 
-  case PH_NONCAPTURES:
-      assert(!pos.is_check());
-      assert(movesPicked >= 0);
+  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;
 
+  case PH_NONCAPTURES:
       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.
-          bestIndex = (pvNode || movesPicked < 12) ? find_best_index() : movesPicked;
-          move = moves[bestIndex].move;
-          moves[bestIndex] = moves[movesPicked++];
-          if (   move != ttMove
-              && move != mateKiller
+          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;
 
   case PH_EVASIONS:
-      assert(pos.is_check());
-      assert(movesPicked >= 0);
-
-      while (movesPicked < numOfMoves)
-      {
-          bestIndex = find_best_index();
-          move = moves[bestIndex].move;
-          moves[bestIndex] = moves[movesPicked++];
-          return move;
-    }
-    break;
+      if (movesPicked < numOfMoves)
+          return moves[movesPicked++].move;
+      break;
 
   case PH_BAD_CAPTURES:
-      assert(!pos.is_check());
-      assert(movesPicked >= 0);
-      // It's probably a good idea to use SEE move ordering here, instead
-      // of just picking the first move.  FIXME
-      while (movesPicked < numOfBadCaptures)
-      {
-          move = badCaptures[movesPicked++].move;
-          if (   move != ttMove
-              && move != mateKiller
-              && pos.pl_move_is_legal(move, pinned))
-              return move;
-      }
+      if (movesPicked < numOfBadCaptures)
+          return badCaptures[movesPicked++].move;
       break;
 
   case PH_QCAPTURES:
-      assert(!pos.is_check());
-      assert(movesPicked >= 0);
-      while (movesPicked < numOfMoves)
-      {
-          bestIndex = (movesPicked < 4 ? find_best_index() : movesPicked);
-          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;
-      }
-      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.pl_move_is_legal(move, pinned))
+          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;
@@ -471,53 +373,3 @@ Move MovePicker::pick_move_from_list() {
   }
   return MOVE_NONE;
 }
-
-
-/// MovePicker::current_move_type() returns the type of the just
-/// 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
-/// 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() {
-
-  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;
-
-}