MovePicker: introduce per square MVV/LVA ordering

[stockfish] / src / movepick.cpp

diff --git a/src/movepick.cpp b/src/movepick.cpp
index b115e8ffb1a9c3b9a6a1c6371ffef62067eea3e3..c51fe69f783baaa2385e07212ae374395867aa2f 100644 (file)
--- 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
@@ -133,6 +134,7 @@ Move MovePicker::get_next_move() {
     case PH_GOOD_CAPTURES:
         numOfMoves = generate_captures(pos, moves);
         score_captures();
+        capSquares = EmptyBoardBB;
         movesPicked = 0;
         break;
 
@@ -233,25 +235,25 @@ 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;\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
+  Move m;
+  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);
+
+      // Ensure moves in history are always sorted as first
+      if (hs > 0)
+          hs += 1000;
+
+      moves[i].score = hs + pos.mg_pst_delta(m);
   }
 }
 
@@ -287,8 +289,11 @@ void MovePicker::score_qcaptures() {
 }
 
 
-/// find_best_index() loops across the moves and returns index of
-/// the highest scored one.
+/// find_best_index() loops across the moves and returns index of\r
+/// the highest scored one. There is also a second version that\r
+/// lowers the priority of moves that attack the same square,\r
+/// so that if the best move that attack a square fails the next\r
+/// move picked attacks a different square if any, not the same one.
 
 int MovePicker::find_best_index() {
 
@@ -303,6 +308,43 @@ int MovePicker::find_best_index() {
   return bestIndex;
 }
 
+int MovePicker::find_best_index(Bitboard* squares, int values[]) {\r
+\r
+  int hs;\r
+  Move m;\r
+  Square to;\r
+  int bestScore = -10000000, bestIndex = -1;\r
+\r
+  for (int i = movesPicked; i < numOfMoves; i++)\r
+  {\r
+      m = moves[i].move;\r
+      to = move_to(m);\r
+      \r
+      if (!bit_is_set(*squares, to))\r
+      {\r
+          // Init at first use\r
+          set_bit(squares, to);\r
+          values[to] = 0;\r
+      }\r
+\r
+      hs = moves[i].score - values[to];\r
+      if (hs > bestScore)\r
+      {\r
+          bestIndex = i;\r
+          bestScore = hs;\r
+      }\r
+  }\r
+\r
+  if (bestIndex != -1)\r
+  {\r
+      // Raise value of the picked square, so next attack\r
+      // to the same square will get low priority.\r
+      to = move_to(moves[bestIndex].move);\r
+      values[to] += 0xB00;\r
+  }\r
+  return bestIndex;\r
+}
+
 
 /// MovePicker::pick_move_from_list() picks the move with the biggest score
 /// from a list of generated moves (moves[] or badCaptures[], depending on