Retire captures pruning

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 378c3d20f1f693d48ec2df4eba1a5ed68f6fc06e..abf2673499ec8be4f0f5ea7a09ad63701ef4542c 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1629,36 +1629,6 @@ namespace {
       // Update current move
       movesSearched[moveCount++] = ss[ply].currentMove = move;
 
-      // Futility pruning for captures
-      // FIXME: test disabling 'Futility pruning for captures'
-      // FIXME: test with 'newDepth < RazorDepth'
-      Color them = opposite_color(pos.side_to_move());
-
-      if (   !isCheck
-          && newDepth < SelectiveDepth
-          && !dangerous
-          && pos.move_is_capture(move)
-          && !pos.move_is_check(move, ci)
-          && !move_is_promotion(move)
-          && move != ttMove
-          && !move_is_ep(move)
-          && (pos.type_of_piece_on(move_to(move)) != PAWN || !pos.pawn_is_passed(them, move_to(move)))) // Do not prune passed pawn captures
-      {
-          int preFutilityValueMargin = 0;
-
-          if (newDepth >= OnePly)
-              preFutilityValueMargin = FutilityMargins[int(newDepth)];
-
-          Value futilityCaptureValue = ss[ply].eval + pos.endgame_value_of_piece_on(move_to(move)) + preFutilityValueMargin + ei.futilityMargin + 90;
-
-          if (futilityCaptureValue < beta)
-          {
-              if (futilityCaptureValue > bestValue)
-                  bestValue = futilityCaptureValue;
-              continue;
-          }
-      }
-
       // Futility pruning
       if (   !isCheck
           && !dangerous
@@ -1805,6 +1775,7 @@ namespace {
     const TTEntry* tte = NULL;
     int moveCount = 0;
     bool pvNode = (beta - alpha != 1);
+    Value oldAlpha = alpha;
 
     // Initialize, and make an early exit in case of an aborted search,
     // an instant draw, maximum ply reached, etc.
@@ -1948,14 +1919,14 @@ namespace {
 
     // Update transposition table
     Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
-    if (bestValue < beta)
+    if (bestValue <= oldAlpha)
     {
         // If bestValue isn't changed it means it is still the static evaluation
         // of the node, so keep this info to avoid a future evaluation() call.
         ValueType type = (bestValue == staticValue && !ei.futilityMargin ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER);
         TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE);
     }
-    else
+    else if (bestValue >= beta)
     {
         move = ss[ply].pv[ply];
         TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move);
@@ -1964,6 +1935,8 @@ namespace {
         if (!pos.move_is_capture_or_promotion(move))
             update_killers(move, ss[ply]);
     }
+    else
+        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, d, ss[ply].pv[ply]);
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);