X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fsearch.cpp;h=8ecdbc309053d5de52aadea392a589e5e109ac15;hb=653bd0817ceea2980474d76198fe527f8b84bf04;hp=ff6bf335d06d695bd17abda8567b7981c8d9e79a;hpb=e1f12aa4e61a8bbb772918c405137acdd85e3eec;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index ff6bf335..8ecdbc30 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -75,7 +75,8 @@ namespace {
   }
 
   constexpr int futility_move_count(bool improving, Depth depth) {
-    return (3 + depth * depth) / (2 - improving);
+    return improving ? (3 + depth * depth)
+                     : (3 + depth * depth) / 2;
   }
 
   // History and stats update bonus, based on depth
@@ -238,6 +239,9 @@ void MainThread::search() {
   bestPreviousScore = bestThread->rootMoves[0].score;
   bestPreviousAverageScore = bestThread->rootMoves[0].averageScore;
 
+  for (Thread* th : Threads)
+    th->previousDepth = bestThread->completedDepth;
+
   // Send again PV info if we have a new best thread
   if (bestThread != this)
       sync_cout << UCI::pv(bestThread->rootPos, bestThread->completedDepth, -VALUE_INFINITE, VALUE_INFINITE) << sync_endl;
@@ -466,8 +470,7 @@ void Thread::search() {
           // If the bestMove is stable over several iterations, reduce time accordingly
           timeReduction = lastBestMoveDepth + 10 < completedDepth ? 1.63 : 0.73;
           double reduction = (1.56 + mainThread->previousTimeReduction) / (2.20 * timeReduction);
-          double bestMoveInstability = 1.073 + std::max(1.0, 2.25 - 9.9 / rootDepth)
-                                              * totBestMoveChanges / Threads.size();
+          double bestMoveInstability = 1 + 1.7 * totBestMoveChanges / Threads.size();
           int complexity = mainThread->complexityAverage.value();
           double complexPosition = std::clamp(1.0 + (complexity - 326) / 1618.1, 0.5, 1.5);
 
@@ -604,8 +607,8 @@ namespace {
     (ss+1)->ttPv         = false;
     (ss+1)->excludedMove = bestMove = MOVE_NONE;
     (ss+2)->killers[0]   = (ss+2)->killers[1] = MOVE_NONE;
+    (ss+2)->cutoffCnt    = 0;
     ss->doubleExtensions = (ss-1)->doubleExtensions;
-    ss->depth            = depth;
     Square prevSq        = to_sq((ss-1)->currentMove);
 
     // Initialize statScore to zero for the grandchildren of the current position.
@@ -866,7 +869,6 @@ namespace {
 
         MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, depth - 3, &captureHistory);
         bool ttPv = ss->ttPv;
-        bool captureOrPromotion;
         ss->ttPv = false;
 
         while ((move = mp.next_move()) != MOVE_NONE)
@@ -874,11 +876,9 @@ namespace {
             {
                 assert(pos.capture(move) || promotion_type(move) == QUEEN);
 
-                captureOrPromotion = true;
-
                 ss->currentMove = move;
                 ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
-                                                                          [captureOrPromotion]
+                                                                          [true]
                                                                           [pos.moved_piece(move)]
                                                                           [to_sq(move)];
 
@@ -1061,7 +1061,7 @@ moves_loop: // When in check, search starts here
           // a reduced search on all the other moves but the ttMove and if the
           // result is lower than ttValue minus a margin, then we will extend the ttMove.
           if (   !rootNode
-              &&  depth >= 4 + 2 * (PvNode && tte->is_pv())
+              &&  depth >= 4 - (thisThread->previousDepth > 27) + 2 * (PvNode && tte->is_pv())
               &&  move == ttMove
               && !excludedMove // Avoid recursive singular search
            /* &&  ttValue != VALUE_NONE Already implicit in the next condition */
@@ -1176,6 +1176,10 @@ moves_loop: // When in check, search starts here
           if (PvNode)
               r -= 1 + 15 / ( 3 + depth );
 
+          // Increase reduction if next ply has a lot of fail high else reset count to 0
+          if ((ss+1)->cutoffCnt > 3 && !PvNode)
+              r++;
+
           ss->statScore =  thisThread->mainHistory[us][from_to(move)]
                          + (*contHist[0])[movedPiece][to_sq(move)]
                          + (*contHist[1])[movedPiece][to_sq(move)]
@@ -1190,8 +1194,7 @@ moves_loop: // When in check, search starts here
           // deeper than the first move (this may lead to hidden double extensions).
           int deeper =   r >= -1                   ? 0
                        : moveCount <= 4            ? 2
-                       : PvNode && depth > 4       ? 1
-                       : cutNode && moveCount <= 8 ? 1
+                       : PvNode || cutNode         ? 1
                        :                             0;
 
           Depth d = std::clamp(newDepth - r, 1, newDepth + deeper);
@@ -1296,14 +1299,29 @@ moves_loop: // When in check, search starts here
                   update_pv(ss->pv, move, (ss+1)->pv);
 
               if (PvNode && value < beta) // Update alpha! Always alpha < beta
+              {
                   alpha = value;
+
+                  // Reduce other moves if we have found at least one score improvement
+                  if (   depth > 2
+                      && depth < 7
+                      && beta  <  VALUE_KNOWN_WIN
+                      && alpha > -VALUE_KNOWN_WIN)
+                     depth -= 1;
+
+                  assert(depth > 0);
+              }
               else
               {
+                  ss->cutoffCnt++;
                   assert(value >= beta); // Fail high
                   break;
               }
           }
       }
+      else
+         ss->cutoffCnt = 0;
+
 
       // If the move is worse than some previously searched move, remember it to update its stats later
       if (move != bestMove)
@@ -1377,6 +1395,7 @@ moves_loop: // When in check, search starts here
 
   // qsearch() is the quiescence search function, which is called by the main search
   // function with zero depth, or recursively with further decreasing depth per call.
+  // (~155 elo)
   template <NodeType nodeType>
   Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) {