X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=80ac9b20b26f351b196e8f55cc09c28d9b05c199;hb=8df17204f4469977604695e4ae5d63ae47a575ff;hp=7a06dad93f94035b046c9384938ce6d8d0b983b1;hpb=0586b51f9c398008f264d78a2888c0d68d9561cb;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index 7a06dad9..80ac9b20 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -440,6 +440,7 @@ namespace {
             if (    depth >= 12
                 && !stop
                 &&  PVSize == 1
+                &&  bestValue > VALUE_MATED_IN_MAX_PLY
                 && (   RootMoves.size() == 1
                     || Time::now() - SearchTime > (TimeMgr.available_time() * 20) / 100))
             {
@@ -532,7 +533,7 @@ namespace {
     if (!RootNode)
     {
         // Step 2. Check for aborted search and immediate draw
-        if (Signals.stop || pos.is_draw<false>() || ss->ply > MAX_PLY)
+        if (Signals.stop || pos.is_draw() || ss->ply > MAX_PLY)
             return DrawValue[pos.side_to_move()];
 
         // Step 3. Mate distance pruning. Even if we mate at the next move our score
@@ -642,10 +643,10 @@ namespace {
         && !ss->skipNullMove
         &&  depth < 4 * ONE_PLY
         && !inCheck
-        &&  eval - FutilityMargins[depth][0] >= beta
+        &&  eval - FutilityMargins[depth][(ss-1)->futMc] >= beta
         &&  abs(beta) < VALUE_MATE_IN_MAX_PLY
         &&  pos.non_pawn_material(pos.side_to_move()))
-        return eval - FutilityMargins[depth][0];
+        return eval - FutilityMargins[depth][(ss-1)->futMc];
 
     // Step 8. Null move search with verification search (is omitted in PV nodes)
     if (   !PvNode
@@ -678,7 +679,7 @@ namespace {
             if (nullValue >= VALUE_MATE_IN_MAX_PLY)
                 nullValue = beta;
 
-            if (depth < 6 * ONE_PLY)
+            if (depth < 12 * ONE_PLY)
                 return nullValue;
 
             // Do verification search at high depths
@@ -745,7 +746,7 @@ namespace {
         && ttMove == MOVE_NONE
         && (PvNode || (!inCheck && ss->staticEval + Value(256) >= beta)))
     {
-        Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
+        Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
 
         ss->skipNullMove = true;
         search<PvNode ? PV : NonPV>(pos, ss, alpha, beta, d);
@@ -851,12 +852,15 @@ split_point_start: // At split points actual search starts from here
       // Update current move (this must be done after singular extension search)
       newDepth = depth - ONE_PLY + ext;
 
+      ss->futMc = 0;
+
       // Step 13. Futility pruning (is omitted in PV nodes)
       if (   !PvNode
           && !captureOrPromotion
           && !inCheck
           && !dangerous
-          &&  move != ttMove)
+       /* &&  move != ttMove Already implicit in the next condition */
+          &&  bestValue > VALUE_MATED_IN_MAX_PLY)
       {
           // Move count based pruning
           if (   depth < 16 * ONE_PLY
@@ -872,15 +876,22 @@ split_point_start: // At split points actual search starts from here
           // Value based pruning
           // We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
           // but fixing this made program slightly weaker.
+          ss->futMc = moveCount;
+
           Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
           futilityValue =  ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
                          + Gain[pos.piece_moved(move)][to_sq(move)];
 
           if (futilityValue < beta)
           {
+              bestValue = std::max(bestValue, futilityValue);
+
               if (SpNode)
+              {
                   splitPoint->mutex.lock();
-
+                  if (bestValue > splitPoint->bestValue)
+                      splitPoint->bestValue = bestValue;
+              }
               continue;
           }
 
@@ -1122,7 +1133,7 @@ split_point_start: // At split points actual search starts from here
     ss->ply = (ss-1)->ply + 1;
 
     // Check for an instant draw or maximum ply reached
-    if (pos.is_draw<true>() || ss->ply > MAX_PLY)
+    if (pos.is_draw() || ss->ply > MAX_PLY)
         return DrawValue[pos.side_to_move()];
 
     // Decide whether or not to include checks, this fixes also the type of
@@ -1218,10 +1229,11 @@ split_point_start: // At split points actual search starts from here
               continue;
           }
 
-          // Prune moves with negative or equal SEE
+          // Prune moves with negative or equal SEE and also moves with positive
+          // SEE where capturing piece loses a tempo and SEE < beta - futilityBase.
           if (   futilityBase < beta
               && depth < DEPTH_ZERO
-              && pos.see(move) <= 0)
+              && pos.see(move, beta - futilityBase) <= 0)
           {
               bestValue = std::max(bestValue, futilityBase);
               continue;
@@ -1571,7 +1583,7 @@ void RootMove::extract_pv_from_tt(Position& pos) {
            && pos.is_pseudo_legal(m = tte->move()) // Local copy, TT could change
            && pos.pl_move_is_legal(m, pos.pinned_pieces())
            && ply < MAX_PLY
-           && (!pos.is_draw<false>() || ply < 2));
+           && (!pos.is_draw() || ply < 2));
 
   pv.push_back(MOVE_NONE); // Must be zero-terminating