Simplify LMR Extensions

xu-shawn · vondele · commit 678d503d8f9c · 2025-08-24T20:10:43.000+02:00
Passed Non-regression STC: LLR: 2.94 (-2.94,2.94) <-1.75,0.25> Total: 236896 W: 61683 L: 61683 D: 113530 Ptnml(0-2): 730, 28057, 60901, 28003, 757 https://tests.stockfishchess.org/tests/view/68a9c20475da51a345a5a6a0 Passed Non-regression LTC: LLR: 2.94 (-2.94,2.94) <-1.75,0.25> Total: 73644 W: 18936 L: 18770 D: 35938 Ptnml(0-2): 33, 7951, 20685, 8123, 30 https://tests.stockfishchess.org/tests/view/68aa95c575da51a345a5a88a closes #6265 Bench: 2693376
diff --git a/src/search.cpp b/src/search.cpp
@@ -1218,8 +1218,7 @@ Value Search::Worker::search(
             // beyond the first move depth.
             // To prevent problems when the max value is less than the min value,
             // std::clamp has been replaced by a more robust implementation.
-            Depth d =
-              std::max(1, std::min(newDepth - r / 1024, newDepth + (PvNode ? 2 : 1))) + PvNode;
+            Depth d = std::max(1, std::min(newDepth - r / 1024, newDepth + 2)) + PvNode;
 
             ss->reduction = newDepth - d;
             value         = -search<NonPV>(pos, ss + 1, -(alpha + 1), -alpha, d, true);
