X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=687bf0a9d2f63712ce31d7947ca36f42a6b3722f;hb=d579db34a3f7a26cd5502e79dafde2a80614d645;hp=28e16609203a7f8262d405ca9cabc6b3434dbf56;hpb=a6a9d828ab4cc35ca0f64207e2ff818a391d1939;p=stockfish

diff --git a/src/search.cpp b/src/search.cpp
index 28e16609..687bf0a9 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -260,6 +260,7 @@ void MainThread::search() {
       bestThread = Threads.get_best_thread();
 
   bestPreviousScore = bestThread->rootMoves[0].score;
+  bestPreviousAverageScore = bestThread->rootMoves[0].averageScore;
 
   // Send again PV info if we have a new best thread
   if (bestThread != this)
@@ -489,8 +490,8 @@ void Thread::search() {
           && !Threads.stop
           && !mainThread->stopOnPonderhit)
       {
-          double fallingEval = (318 + 6 * (mainThread->bestPreviousScore - bestValue)
-                                    + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0;
+          double fallingEval = (142 + 12 * (mainThread->bestPreviousAverageScore - bestValue)
+                                    +  6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0;
           fallingEval = std::clamp(fallingEval, 0.5, 1.5);
 
           // If the bestMove is stable over several iterations, reduce time accordingly
@@ -1087,7 +1088,7 @@ 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 >= 7
+          &&  depth >= 6 + 2 * (PvNode && tte->is_pv())
           &&  move == ttMove
           && !excludedMove // Avoid recursive singular search
        /* &&  ttValue != VALUE_NONE Already implicit in the next condition */
@@ -1163,6 +1164,8 @@ moves_loop: // When in check, search starts here
       // Step 15. Make the move
       pos.do_move(move, st, givesCheck);
 
+      bool doDeeperSearch = false;
+
       // Step 16. Late moves reduction / extension (LMR, ~200 Elo)
       // We use various heuristics for the sons of a node after the first son has
       // been searched. In general we would like to reduce them, but there are many
@@ -1235,6 +1238,7 @@ moves_loop: // When in check, search starts here
 
           // If the son is reduced and fails high it will be re-searched at full depth
           doFullDepthSearch = value > alpha && d < newDepth;
+          doDeeperSearch = value > alpha + 88;
           didLMR = true;
       }
       else
@@ -1246,7 +1250,7 @@ moves_loop: // When in check, search starts here
       // Step 17. Full depth search when LMR is skipped or fails high
       if (doFullDepthSearch)
       {
-          value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
+          value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth + doDeeperSearch, !cutNode);
 
           // If the move passed LMR update its stats
           if (didLMR && !captureOrPromotion)
@@ -1378,7 +1382,15 @@ moves_loop: // When in check, search starts here
     // Bonus for prior countermove that caused the fail low
     else if (   (depth >= 3 || PvNode)
              && !priorCapture)
-        update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + (PvNode || cutNode)));
+    {
+        //Assign extra bonus if current node is PvNode or cutNode
+        //or fail low was really bad
+        bool extraBonus =    PvNode
+                          || cutNode
+                          || bestValue < alpha - 94 * depth;
+
+        update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + extraBonus));
+    }
 
     if (PvNode)
         bestValue = std::min(bestValue, maxValue);