X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=b7a242f98470422cfeacd7041cefdd917d3fe7fc;hp=0de9e8f9c85da4d7800ccdd32086eb831f0a0454;hb=eed508b4445057cd26bfb95ab5cd754ac96629fd;hpb=13d1f0ae4301b86c610a58332c3c19d9101704da

diff --git a/src/search.cpp b/src/search.cpp
index 0de9e8f9..b7a242f9 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -63,12 +63,10 @@ namespace {
   inline Value razor_margin(Depth d) { return Value(512 + 16 * int(d)); }
 
   // Futility lookup tables (initialized at startup) and their access functions
-  Value FutilityMargins[14][64]; // [depth][moveNumber]
   int FutilityMoveCounts[2][32]; // [improving][depth]
 
-  inline Value futility_margin(Depth d, int mn) {
-    assert(DEPTH_ZERO <= d && d < 7 * ONE_PLY);
-    return FutilityMargins[d][std::min(mn, 63)];
+  inline Value futility_margin(Depth d) {
+    return Value(100 * int(d));
   }
 
   // Reduction lookup tables (initialized at startup) and their access function
@@ -144,10 +142,6 @@ void Search::init() {
           Reductions[0][0][hd][mc] += ONE_PLY / 2;
   }
 
-  // Init futility margins array
-  for (d = 0; d < 14; ++d) for (mc = 0; mc < 64; ++mc)
-      FutilityMargins[d][mc] = Value(112 * int(2.9 * log(d >= 1 ? double(d) : 1.0)) - 8 * mc + 45);
-
   // Init futility move count array
   for (d = 0; d < 32; ++d)
   {
@@ -523,7 +517,6 @@ namespace {
     bestValue = -VALUE_INFINITE;
     ss->currentMove = threatMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
     ss->ply = (ss-1)->ply + 1;
-    ss->futilityMoveCount = 0;
     (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
     (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
 
@@ -624,15 +617,15 @@ namespace {
             return v;
     }
 
-    // Step 7. post-Futility pruning (skipped when in check)
+    // Step 7. Futility pruning: child node (skipped when in check)
     if (   !PvNode
         && !ss->skipNullMove
         &&  depth < 7 * ONE_PLY
-        &&  eval - futility_margin(depth, (ss-1)->futilityMoveCount) >= beta
+        &&  eval - futility_margin(depth) >= beta
         &&  abs(beta) < VALUE_MATE_IN_MAX_PLY
         &&  abs(eval) < VALUE_KNOWN_WIN
         &&  pos.non_pawn_material(pos.side_to_move()))
-        return eval - futility_margin(depth, (ss-1)->futilityMoveCount);
+        return eval - futility_margin(depth);
 
     // Step 8. Null move search with verification search (is omitted in PV nodes)
     if (   !PvNode
@@ -834,13 +827,13 @@ moves_loop: // When in check and at SpNode search starts from here
 
       // Update current move (this must be done after singular extension search)
       newDepth = depth - ONE_PLY + ext;
-      Depth predictedDepth = newDepth - reduction<PvNode>(improving, depth, moveCount);
 
-      // Step 13. Futility pruning (is omitted in PV nodes)
+      // Step 13. Pruning at shallow depth (exclude PV nodes)
       if (   !PvNode
           && !captureOrPromotion
           && !inCheck
           && !dangerous
+       /* &&  move != ttMove Already implicit in the next condition */
           &&  bestValue > VALUE_MATED_IN_MAX_PLY)
       {
           // Move count based pruning
@@ -854,6 +847,27 @@ moves_loop: // When in check and at SpNode search starts from here
               continue;
           }
 
+          Depth predictedDepth = newDepth - reduction<PvNode>(improving, depth, moveCount);
+
+          // Futility pruning: parent node
+          if (predictedDepth < 7 * ONE_PLY)
+          {
+              Value futilityValue = ss->staticEval + futility_margin(predictedDepth) + Value(128);
+
+              if (futilityValue <= alpha)
+              {
+                  bestValue = std::max(bestValue, futilityValue);
+
+                  if (SpNode)
+                  {
+                      splitPoint->mutex.lock();
+                      if (bestValue > splitPoint->bestValue)
+                          splitPoint->bestValue = bestValue;
+                  }
+                  continue;
+              }
+          }
+
           // Prune moves with negative SEE at low depths
           if (   predictedDepth < 4 * ONE_PLY
               && pos.see_sign(move) < 0)
@@ -864,12 +878,7 @@ moves_loop: // When in check and at SpNode search starts from here
               continue;
           }
 
-          // We have not pruned the move that will be searched, but remember how
-          // far in the move list we are to be more aggressive in the child node.
-          ss->futilityMoveCount = moveCount;
       }
-      else
-          ss->futilityMoveCount = 0;
 
       // Check for legality only before to do the move
       if (!RootNode && !SpNode && !pos.legal(move, ci.pinned))