X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=c9526ec3c683e38a013089dfcd98bb661f3f2c0e;hp=639c5bc55bf9a1d6d676d29bf2678ed80241cccf;hb=8bb7a737087ca82cb97380bf06bbfa659dec1f73;hpb=9fff27220917d706988185cbd847e3f355a7fe09

diff --git a/src/search.cpp b/src/search.cpp
index 639c5bc5..c9526ec3 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -387,7 +387,7 @@ void Thread::search() {
           if (rootDepth >= 5 * ONE_PLY)
           {
               Value previousScore = rootMoves[pvIdx].previousScore;
-              delta = Value(18);
+              delta = Value(20);
               alpha = std::max(previousScore - delta,-VALUE_INFINITE);
               beta  = std::min(previousScore + delta, VALUE_INFINITE);
 
@@ -401,9 +401,11 @@ void Thread::search() {
           // Start with a small aspiration window and, in the case of a fail
           // high/low, re-search with a bigger window until we don't fail
           // high/low anymore.
+          int failedHighCnt = 0;
           while (true)
           {
-              bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false);
+              Depth adjustedDepth = std::max(ONE_PLY, rootDepth - failedHighCnt * ONE_PLY);
+              bestValue = ::search<PV>(rootPos, ss, alpha, beta, adjustedDepth, false);
 
               // Bring the best move to the front. It is critical that sorting
               // is done with a stable algorithm because all the values but the
@@ -436,12 +438,17 @@ void Thread::search() {
 
                   if (mainThread)
                   {
+                      failedHighCnt = 0;
                       failedLow = true;
                       Threads.stopOnPonderhit = false;
                   }
               }
               else if (bestValue >= beta)
+              {
                   beta = std::min(bestValue + delta, VALUE_INFINITE);
+                  if (mainThread)
+                	  ++failedHighCnt;
+              }
               else
                   break;