Effectively use MVV/LVA in MovePicker::score_captures()

[stockfish] / src / movepick.cpp

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 68f03a30ae0415803498305d0bdf880c0b6d7727..5f170297b2a26c9c9cae15f73a9415d33e0a0645 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -207,7 +207,7 @@ 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.
   for (int i = 0; i < numOfMoves; i++)
@@ -226,16 +226,28 @@ void MovePicker::score_captures() {
 }
 
 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);
+  // 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;\r
+  int hs;\r
+\r
+  for (int i = 0; i < numOfMoves; i++)\r
+  {\r
+      m = moves[i].move;\r
+\r
+      if (m == killer1)\r
+          hs = HistoryMax + 2;\r
+      else if (m == killer2)\r
+          hs = HistoryMax + 1;\r
+      else\r
+          hs = H.move_ordering_score(pos.piece_on(move_from(m)), m);\r
+\r
+      // Ensure moves in history are always sorted as first\r
+      if (hs > 0)\r
+          hs += 1000;\r
+\r
+      moves[i].score = hs + pos.mg_pst_delta(m);\r
   }
 }
 
@@ -266,7 +278,7 @@ 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)));
   }
 }