X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=c748f1ff4251424b91fb1b8f8b6db5a87057502b;hb=d4d1cec29631f041adeec98adc5893b5c6a54969;hp=55af6abab1c13bd4acba83b18d2744210cf967b8;hpb=ea0f34120fbc1ab7aa8047a1319714b87a1f3b87;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index 55af6aba..c748f1ff 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((11 * d + 284) * d - 363 , 1650);
+    return std::min(350 * d - 400, 1650);
   }
 
   // Add a small random component to draw evaluations to avoid 3-fold blindness
@@ -96,7 +96,10 @@ namespace {
   struct Skill {
     Skill(int skill_level, int uci_elo) {
         if (uci_elo)
-            level = std::clamp(std::pow((uci_elo - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0);
+        {
+            double e = double(uci_elo - 1320) / (3190 - 1320);
+            level = std::clamp((((37.2473 * e - 40.8525) * e + 22.2943) * e - 0.311438), 0.0, 19.0);
+        }
         else
             level = double(skill_level);
     }
@@ -239,9 +242,6 @@ 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) << sync_endl;
@@ -1023,12 +1023,17 @@ moves_loop: // When in check, search starts here
 
               history += 2 * thisThread->mainHistory[us][from_to(move)];
 
+              lmrDepth += history / 7208;
+              lmrDepth = std::max(lmrDepth, -2);
+
               // Futility pruning: parent node (~13 Elo)
               if (   !ss->inCheck
                   && lmrDepth < 13
-                  && ss->staticEval + 103 + 136 * lmrDepth + history / 53 <= alpha)
+                  && ss->staticEval + 103 + 136 * lmrDepth <= alpha)
                   continue;
 
+              lmrDepth = std::max(lmrDepth, 0);
+
               // Prune moves with negative SEE (~4 Elo)
               if (!pos.see_ge(move, Value(-25 * lmrDepth * lmrDepth - 16 * lmrDepth)))
                   continue;
@@ -1045,7 +1050,7 @@ 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 - (thisThread->previousDepth > 24) + 2 * (PvNode && tte->is_pv())
+              &&  depth >= 4 - (thisThread->completedDepth > 22) + 2 * (PvNode && tte->is_pv())
               &&  move == ttMove
               && !excludedMove // Avoid recursive singular search
            /* &&  ttValue != VALUE_NONE Already implicit in the next condition */
@@ -1215,6 +1220,10 @@ moves_loop: // When in check, search starts here
       // Step 18. Full depth search when LMR is skipped. If expected reduction is high, reduce its depth by 1.
       else if (!PvNode || moveCount > 1)
       {
+               // Increase reduction for cut nodes and not ttMove (~1 Elo)
+               if (!ttMove && cutNode)
+                         r += 2;
+
                value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth - (r > 4), !cutNode);
       }