X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fsearch.cpp;h=7043e49dbe2bd8cac54fee35c5365baad1685cd0;hb=7133598a98301cf84857d39194026b876da48b96;hp=31ae5377086cda0fa70a2514259e66037dd06303;hpb=1aab5b4b055dffae5e2a2cf9958d3d0d79f66cb4;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index 31ae5377..7043e49d 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -61,10 +61,6 @@ namespace {
   // Different node types, used as a template parameter
   enum NodeType { NonPV, PV };
 
-  // Sizes and phases of the skip-blocks, used for distributing search depths across the threads
-  constexpr int SkipSize[]  = { 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4 };
-  constexpr int SkipPhase[] = { 0, 1, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 7 };
-
   // Razor and futility margins
   constexpr int RazorMargin = 600;
   Value futility_margin(Depth d, bool improving) {
@@ -297,7 +293,6 @@ void Thread::search() {
   MainThread* mainThread = (this == Threads.main() ? Threads.main() : nullptr);
   double timeReduction = 1.0;
   Color us = rootPos.side_to_move();
-  bool failedLow;
 
   std::memset(ss-7, 0, 10 * sizeof(Stack));
   for (int i = 7; i > 0; i--)
@@ -308,7 +303,7 @@ void Thread::search() {
   beta = VALUE_INFINITE;
 
   if (mainThread)
-      mainThread->bestMoveChanges = 0, failedLow = false;
+      mainThread->bestMoveChanges = 0;
 
   size_t multiPV = Options["MultiPV"];
   Skill skill(Options["Skill Level"]);
@@ -339,17 +334,9 @@ void Thread::search() {
          && !Threads.stop
          && !(Limits.depth && mainThread && rootDepth / ONE_PLY > Limits.depth))
   {
-      // Distribute search depths across the helper threads
-      if (idx > 0)
-      {
-          int i = (idx - 1) % 20;
-          if (((rootDepth / ONE_PLY + SkipPhase[i]) / SkipSize[i]) % 2)
-              continue;  // Retry with an incremented rootDepth
-      }
-
       // Age out PV variability metric
       if (mainThread)
-          mainThread->bestMoveChanges *= 0.517, failedLow = false;
+          mainThread->bestMoveChanges *= 0.517;
 
       // Save the last iteration's scores before first PV line is searched and
       // all the move scores except the (new) PV are set to -VALUE_INFINITE.
@@ -429,7 +416,6 @@ void Thread::search() {
                   if (mainThread)
                   {
                       failedHighCnt = 0;
-                      failedLow = true;
                       mainThread->stopOnPonderhit = false;
                   }
               }
@@ -481,19 +467,19 @@ void Thread::search() {
           && !Threads.stop
           && !mainThread->stopOnPonderhit)
       {
-          double fallingEval = (306 + 119 * failedLow + 6 * (mainThread->previousScore - bestValue)) / 581.0;
+          double fallingEval = (306 + 9 * (mainThread->previousScore - bestValue)) / 581.0;
           fallingEval        = std::max(0.5, std::min(1.5, fallingEval));
 
           // If the bestMove is stable over several iterations, reduce time accordingly
           timeReduction = lastBestMoveDepth + 10 * ONE_PLY < completedDepth ? 1.95 : 1.0;
+          double reduction = std::pow(mainThread->previousTimeReduction, 0.528) / timeReduction;
 
           // Use part of the gained time from a previous stable move for the current move
           double bestMoveInstability = 1.0 + mainThread->bestMoveChanges;
-          bestMoveInstability *= std::pow(mainThread->previousTimeReduction, 0.528) / timeReduction;
 
           // Stop the search if we have only one legal move, or if available time elapsed
           if (   rootMoves.size() == 1
-              || Time.elapsed() > Time.optimum() * bestMoveInstability * fallingEval)
+              || Time.elapsed() > Time.optimum() * fallingEval * reduction * bestMoveInstability)
           {
               // If we are allowed to ponder do not stop the search now but
               // keep pondering until the GUI sends "ponderhit" or "stop".
@@ -914,12 +900,13 @@ moves_loop: // When in check, search starts from here
           &&  move == ttMove
           && !rootNode
           && !excludedMove // Avoid recursive singular search
-          &&  ttValue != VALUE_NONE
+      /*  &&  ttValue != VALUE_NONE Already implicit in the next condition */
+          &&  abs(ttValue) < VALUE_KNOWN_WIN
           && (tte->bound() & BOUND_LOWER)
           &&  tte->depth() >= depth - 3 * ONE_PLY
           &&  pos.legal(move))
       {
-          Value singularBeta = std::max(ttValue - 2 * depth / ONE_PLY, -VALUE_MATE);
+          Value singularBeta = ttValue - 2 * depth / ONE_PLY;
           ss->excludedMove = move;
           value = search<NonPV>(pos, ss, singularBeta - 1, singularBeta, depth / 2, cutNode);
           ss->excludedMove = MOVE_NONE;
@@ -983,8 +970,7 @@ moves_loop: // When in check, search starts from here
               if (!pos.see_ge(move, Value(-29 * lmrDepth * lmrDepth)))
                   continue;
           }
-          else if (   !extension // (~20 Elo)
-                   && !pos.see_ge(move, -PawnValueEg * (depth / ONE_PLY)))
+          else if (!pos.see_ge(move, -PawnValueEg * (depth / ONE_PLY))) // (~20 Elo)
                   continue;
       }