X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=c48b74bcc76ddc0761cdb9c44d961dffa4b0f2c0;hb=dabaf2220fe0c77400a5f71a91952f510e6a126b;hp=c41df1f0fdcb7005526a20ba2b349cfaa3c80542;hpb=a85928e7ecf36431aee5bf48d46bfea4e6085cb7;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index c41df1f0..c48b74bc 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -779,8 +779,10 @@ namespace {
                ? ss->staticEval > (ss-4)->staticEval || (ss-4)->staticEval == VALUE_NONE
                : ss->staticEval > (ss-2)->staticEval;
 
-    // Step 7. Futility pruning: child node (~50 Elo)
+    // Step 7. Futility pruning: child node (~50 Elo).
+    // The depth condition is important for mate finding.
     if (   !PvNode
+        &&  depth < 9
         &&  eval - futility_margin(depth, improving) >= beta
         &&  eval < VALUE_KNOWN_WIN) // Do not return unproven wins
         return eval;
@@ -907,7 +909,7 @@ namespace {
         && !ttMove)
         depth -= 2;
 
-moves_loop: // When in check, search starts from here
+moves_loop: // When in check, search starts here
 
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
 
@@ -989,7 +991,7 @@ moves_loop: // When in check, search starts from here
       // Calculate new depth for this move
       newDepth = depth - 1;
 
-      // Step 13. Pruning at shallow depth (~200 Elo)
+      // Step 13. Pruning at shallow depth (~200 Elo). Depth conditions are important for mate finding.
       if (  !rootNode
           && pos.non_pawn_material(us)
           && bestValue > VALUE_TB_LOSS_IN_MAX_PLY)
@@ -1017,21 +1019,18 @@ moves_loop: // When in check, search starts from here
           {
               // Continuation history based pruning (~20 Elo)
               if (   lmrDepth < 5
-                  && (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold
-                  && (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold)
+                  && (*contHist[0])[movedPiece][to_sq(move)] < 23 - 23 * depth * depth
+                  && (*contHist[1])[movedPiece][to_sq(move)] < 23 - 23 * depth * depth)
                   continue;
 
               // Futility pruning: parent node (~5 Elo)
               if (   !ss->inCheck
-                  && ss->staticEval + 174 + 157 * lmrDepth <= alpha
-                  &&  (*contHist[0])[movedPiece][to_sq(move)]
-                    + (*contHist[1])[movedPiece][to_sq(move)]
-                    + (*contHist[3])[movedPiece][to_sq(move)]
-                    + (*contHist[5])[movedPiece][to_sq(move)] / 3 < 28255)
+                  && lmrDepth < 7
+                  && ss->staticEval + 174 + 157 * lmrDepth <= alpha)
                   continue;
 
               // Prune moves with negative SEE (~20 Elo)
-              if (!pos.see_ge(move, Value(-(30 - std::min(lmrDepth, 18)) * lmrDepth * lmrDepth)))
+              if (!pos.see_ge(move, Value(-21 * lmrDepth * lmrDepth - 21 * lmrDepth)))
                   continue;
           }
       }
@@ -1159,21 +1158,18 @@ moves_loop: // When in check, search starts from here
           if (cutNode && move != ss->killers[0])
               r += 2;
 
-          if (!captureOrPromotion)
-          {
-              // Increase reduction if ttMove is a capture (~3 Elo)
-              if (ttCapture)
-                  r++;
-
-              ss->statScore =  thisThread->mainHistory[us][from_to(move)]
-                             + (*contHist[0])[movedPiece][to_sq(move)]
-                             + (*contHist[1])[movedPiece][to_sq(move)]
-                             + (*contHist[3])[movedPiece][to_sq(move)]
-                             - 4923;
-
-              // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
-              r -= ss->statScore / 14721;
-          }
+          // Increase reduction if ttMove is a capture (~3 Elo)
+          if (ttCapture)
+              r++;
+
+          ss->statScore =  thisThread->mainHistory[us][from_to(move)]
+                         + (*contHist[0])[movedPiece][to_sq(move)]
+                         + (*contHist[1])[movedPiece][to_sq(move)]
+                         + (*contHist[3])[movedPiece][to_sq(move)]
+                         - 4923;
+
+          // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
+          r -= ss->statScore / 14721;
 
           // In general we want to cap the LMR depth search at newDepth. But if
           // reductions are really negative and movecount is low, we allow this move