Further increase SEE prune depth

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 40a887c27821654b7f26cb2f2a0bb3131080a1db..7a06dad93f94035b046c9384938ce6d8d0b983b1 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -885,7 +885,7 @@ split_point_start: // At split points actual search starts from here
           }
 
           // Prune moves with negative SEE at low depths
-          if (   predictedDepth < 3 * ONE_PLY
+          if (   predictedDepth < 4 * ONE_PLY
               && pos.see_sign(move) < 0)
           {
               if (SpNode)
@@ -1125,6 +1125,12 @@ split_point_start: // At split points actual search starts from here
     if (pos.is_draw<true>() || ss->ply > MAX_PLY)
         return DrawValue[pos.side_to_move()];
 
+    // Decide whether or not to include checks, this fixes also the type of
+    // TT entry depth that we are going to use. Note that in qsearch we use
+    // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
+    ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
+                                                  : DEPTH_QS_NO_CHECKS;
+
     // Transposition table lookup. At PV nodes, we don't use the TT for
     // pruning, but only for move ordering.
     posKey = pos.key();
@@ -1132,11 +1138,6 @@ split_point_start: // At split points actual search starts from here
     ttMove = tte ? tte->move() : MOVE_NONE;
     ttValue = tte ? value_from_tt(tte->value(),ss->ply) : VALUE_NONE;
 
-    // Decide whether or not to include checks, this fixes also the type of
-    // TT entry depth that we are going to use. Note that in qsearch we use
-    // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
-    ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
-                                                  : DEPTH_QS_NO_CHECKS;
     if (   tte
         && tte->depth() >= ttDepth
         && ttValue != VALUE_NONE // Only in case of TT access race