X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=4507460a5b639e40573e6af83e35b6f70eaa6767;hp=b58a344a597b61103c809706c4893aff48451553;hb=39af98c807d236b6511b6e399caf40102398900c;hpb=726e90ccfaea85c5831ad4834a6a08f5bec3f2f2

diff --git a/src/search.cpp b/src/search.cpp
index b58a344a..4507460a 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -81,7 +81,7 @@ namespace {
 
   // History and stats update bonus, based on depth
   int stat_bonus(Depth d) {
-    return std::min((12 * d + 282) * d - 349 , 1594);
+    return std::min((12 * d + 282) * d - 349 , 1480);
   }
 
   // Add a small random component to draw evaluations to avoid 3-fold blindness
@@ -1066,7 +1066,7 @@ moves_loop: // When in check, search starts here
                   // Avoid search explosion by limiting the number of double extensions
                   if (  !PvNode
                       && value < singularBeta - 25
-                      && ss->doubleExtensions <= 9)
+                      && ss->doubleExtensions <= 10)
                   {
                       extension = 2;
                       depth += depth < 12;
@@ -1175,7 +1175,7 @@ moves_loop: // When in check, search starts here
                          - 4433;
 
           // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
-          r -= ss->statScore / (13628 + 4000 * (depth > 7 && depth < 19));
+          r -= ss->statScore / (13000 + 4152 * (depth > 7 && depth < 19));
 
           // In general we want to cap the LMR depth search at newDepth, but when
           // reduction is negative, we allow this move a limited search extension
@@ -1190,9 +1190,12 @@ moves_loop: // When in check, search starts here
               // Adjust full depth search based on LMR results - if result
               // was good enough search deeper, if it was bad enough search shallower
               const bool doDeeperSearch = value > (alpha + 64 + 11 * (newDepth - d));
+              const bool doEvenDeeperSearch = value > alpha + 582 && ss->doubleExtensions <= 5;
               const bool doShallowerSearch = value < bestValue + newDepth;
 
-              newDepth += doDeeperSearch - doShallowerSearch;
+              ss->doubleExtensions = ss->doubleExtensions + doEvenDeeperSearch;
+
+              newDepth += doDeeperSearch - doShallowerSearch + doEvenDeeperSearch;
 
               if (newDepth > d)
                   value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);