Tweak futility pruning constants

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 6146bdf6b5ae9ac24f48cb2e3e3ca831bf8f7618..035dd40a5c7c17d4b92dd11a2ff35f8d1b709cbb 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -393,6 +393,8 @@ void Thread::search() {
   contempt = (us == WHITE ?  make_score(ct, ct / 2)
                           : -make_score(ct, ct / 2));
 
+  int searchAgainCounter = 0;
+
   // Iterative deepening loop until requested to stop or the target depth is reached
   while (   ++rootDepth < MAX_PLY
          && !Threads.stop
@@ -410,6 +412,9 @@ void Thread::search() {
       size_t pvFirst = 0;
       pvLast = 0;
 
+      if (!Threads.increaseDepth)
+         searchAgainCounter++;
+
       // MultiPV loop. We perform a full root search for each PV line
       for (pvIdx = 0; pvIdx < multiPV && !Threads.stop; ++pvIdx)
       {
@@ -445,7 +450,7 @@ void Thread::search() {
           int failedHighCnt = 0;
           while (true)
           {
-              Depth adjustedDepth = std::max(1, rootDepth - failedHighCnt);
+              Depth adjustedDepth = std::max(1, rootDepth - failedHighCnt - searchAgainCounter);
               bestValue = ::search<PV>(rootPos, ss, alpha, beta, adjustedDepth, false);
 
               // Bring the best move to the front. It is critical that sorting
@@ -558,6 +563,12 @@ void Thread::search() {
               else
                   Threads.stop = true;
           }
+          else if (   Threads.increaseDepth
+                   && !mainThread->ponder
+                   && Time.elapsed() > Time.optimum() * fallingEval * reduction * bestMoveInstability * 0.6)
+                   Threads.increaseDepth = false;
+          else
+                   Threads.increaseDepth = true;
       }
 
       mainThread->iterValue[iterIdx] = bestValue;
@@ -1005,11 +1016,11 @@ moves_loop: // When in check, search starts from here
               // Futility pruning: parent node (~5 Elo)
               if (   lmrDepth < 6
                   && !inCheck
-                  && ss->staticEval + 255 + 182 * lmrDepth <= alpha
+                  && ss->staticEval + 235 + 172 * lmrDepth <= alpha
                   &&  thisThread->mainHistory[us][from_to(move)]
                     + (*contHist[0])[movedPiece][to_sq(move)]
                     + (*contHist[1])[movedPiece][to_sq(move)]
-                    + (*contHist[3])[movedPiece][to_sq(move)] < 30000)
+                    + (*contHist[3])[movedPiece][to_sq(move)] < 25000)
                   continue;
 
               // Prune moves with negative SEE (~20 Elo)