cutnode and movecount lmr extension simplification

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index ff7b996be5710e05ef0f0a46605e8d6f00fc8ba0..8ecdbc309053d5de52aadea392a589e5e109ac15 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -75,7 +75,8 @@ namespace {
   }
 
   constexpr int futility_move_count(bool improving, Depth depth) {
-    return (3 + depth * depth) / (2 - improving);
+    return improving ? (3 + depth * depth)
+                     : (3 + depth * depth) / 2;
   }
 
   // History and stats update bonus, based on depth
@@ -1193,8 +1194,7 @@ moves_loop: // When in check, search starts here
           // deeper than the first move (this may lead to hidden double extensions).
           int deeper =   r >= -1                   ? 0
                        : moveCount <= 4            ? 2
-                       : PvNode                    ? 1
-                       : cutNode && moveCount <= 8 ? 1
+                       : PvNode || cutNode         ? 1
                        :                             0;
 
           Depth d = std::clamp(newDepth - r, 1, newDepth + deeper);
@@ -1395,6 +1395,7 @@ moves_loop: // When in check, search starts here
 
   // qsearch() is the quiescence search function, which is called by the main search
   // function with zero depth, or recursively with further decreasing depth per call.
+  // (~155 elo)
   template <NodeType nodeType>
   Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) {