Disable per-square MVV/LVA for now

[stockfish] / src / movepick.cpp

diff --git a/src/movepick.cpp b/src/movepick.cpp
index c51fe69f783baaa2385e07212ae374395867aa2f..02116b1cbfaf4f177adad36c6e7620e066578294 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -26,6 +26,7 @@
 #include <cassert>
 
 #include "history.h"
+#include "evaluate.h"
 #include "movegen.h"
 #include "movepick.h"
 #include "search.h"
@@ -44,7 +45,9 @@ namespace {
   int MainSearchPhaseIndex;
   int EvasionsPhaseIndex;
   int QsearchWithChecksPhaseIndex;
+  int QsearchNoCapturesPhaseIndex;
   int QsearchWithoutChecksPhaseIndex;
+  int NoMovesPhaseIndex;
 
 }
 
@@ -62,9 +65,9 @@ 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,
+                       Move mk, Move k1, Move k2, Depth d, EvalInfo* ei) : pos(p) {
+  pvNode = pv;
   ttMove = ttm;
   mateKiller = (mk == ttm)? MOVE_NONE : mk;
   killer1 = k1;
@@ -73,17 +76,25 @@ MovePicker::MovePicker(const Position& p, bool pvnode, Move ttm, Move mk,
   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 them in case we know are zero.
+  Color us = pos.side_to_move();
+  Color them = opposite_color(us);
+  bool noAttacks = ei && (ei->attackedBy[us][0] & pos.pieces_of_color(them)) == 0;
+  bool noCaptures = noAttacks && (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;
+      phaseIndex = (noCaptures ? NoMovesPhaseIndex : QsearchWithoutChecksPhaseIndex);
+
 
+  dc = p.discovered_check_candidates(us);
   pinned = p.pinned_pieces(p.side_to_move());
 
   finished = false;
@@ -134,7 +145,6 @@ Move MovePicker::get_next_move() {
     case PH_GOOD_CAPTURES:
         numOfMoves = generate_captures(pos, moves);
         score_captures();
-        capSquares = EmptyBoardBB;
         movesPicked = 0;
         break;
 
@@ -212,6 +222,8 @@ void MovePicker::score_captures() {
   // 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;
 
@@ -226,8 +238,15 @@ void MovePicker::score_captures() {
           else
               moves[i].score = int(pos.midgame_value_of_piece_on(move_to(m)))
                               -int(pos.type_of_piece_on(move_from(m)));
-      } else
+      }
+      else
+      {
+          // Losing capture, move it to the badCaptures[] array
+          assert(numOfBadCaptures < 63);
           moves[i].score = seeValue;
+          badCaptures[numOfBadCaptures++] = moves[i];
+          moves[i--] = moves[--numOfMoves];
+      }
   }
 }
 
@@ -350,9 +369,6 @@ int MovePicker::find_best_index(Bitboard* squares, int values[]) {
 /// 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() {
 
@@ -366,23 +382,8 @@ Move MovePicker::pick_move_from_list() {
 
       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;
-              }
-          }
+          bestIndex = find_best_index();
+
           if (bestIndex != -1) // Found a good capture
           {
               move = moves[bestIndex].move;
@@ -502,8 +503,9 @@ 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() {
 
@@ -532,8 +534,17 @@ 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;
 }