Introduce Correction History Quad Extensions

bench 1574831
official-stockfish · Jan 12, 2025 · d6dc0ff · d6dc0ff
1 parent c76c179
commit d6dc0ff
Showing 1 changed file with 8 additions and 3 deletions.
diff --git a/src/search.cpp b/src/search.cpp
@@ -1082,11 +1082,16 @@ Value Search::Worker::search(
 
                 if (value < singularBeta)
                 {
-                    int doubleMargin = 249 * PvNode - 194 * !ttCapture;
-                    int tripleMargin = 94 + 287 * PvNode - 249 * !ttCapture + 99 * ss->ttPv;
+                    int corrValAdj   = std::abs(correctionValue) / 262144;
+                    int doubleMargin = 249 * PvNode - 194 * !ttCapture - corrValAdj;
+                    int tripleMargin =
+                      94 + 287 * PvNode - 249 * !ttCapture + 99 * ss->ttPv - corrValAdj;
+                    int quadMargin =
+                      394 + 287 * PvNode - 249 * !ttCapture + 99 * ss->ttPv - corrValAdj;
 
                     extension = 1 + (value < singularBeta - doubleMargin)
-                              + (value < singularBeta - tripleMargin);
+                              + (value < singularBeta - tripleMargin)
+                              + (value < singularBeta - quadMargin);
 
                     depth += ((!PvNode) && (depth < 14));
                 }