MovePicker: avoid calling see() for LxH and equal captures

[stockfish] / src / movepick.cpp

diff --git a/src/movepick.cpp b/src/movepick.cpp
index ca0d8681a1d0515f4fc8c87110ab34124138ecd5..95bbddba670788af7d2b937a72ddb4c28a791a31 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -72,7 +72,6 @@ MovePicker::MovePicker(const Position& p, bool pv, Move ttm,
   mateKiller = (ss.mateKiller == ttm)? MOVE_NONE : ss.mateKiller;
   killer1 = ss.killers[0];
   killer2 = ss.killers[1];
-  threatMove = ss.threatMove;
   depth = d;
   movesPicked = 0;
   numOfMoves = 0;
@@ -229,18 +228,29 @@ void MovePicker::score_captures() {
   // to the badCaptures[] array.
   Move m;
   int seeValue;
+  Square from, to;
 
   for (int i = 0; i < numOfMoves; i++)
   {
       m = moves[i].move;
-      seeValue = pos.see(m);
+      from = move_from(m);
+      to = move_to(m);
+
+      bool hxl = ( int(pos.midgame_value_of_piece_on(from))
+                  -int(pos.midgame_value_of_piece_on(to)) > 0)
+                || pos.type_of_piece_on(from) == KING;
+
+      // Avoid calling see() for LxH and equal captures because
+      // SEE is always >= 0 and we order for MVV/LVA anyway.
+      seeValue = (hxl ? pos.see(m) : 0);
+
       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)));
+              moves[i].score = int(pos.midgame_value_of_piece_on(to))
+                              -int(pos.type_of_piece_on(from));
       }
       else
       {
@@ -271,11 +281,6 @@ void MovePicker::score_noncaptures() {
       else
           hs = H.move_ordering_score(pos.piece_on(move_from(m)), m);
 
-      // If the null move was refuted by a capture then give a
-      // bonus if we move away the captured piece.
-      if (threatMove != MOVE_NONE && move_from(m) == move_to(threatMove))
-          hs *= 3;
-
       // Ensure history is always preferred to pst
       if (hs > 0)
           hs += 1000;