Less futility pruning.

locutus2 · snicolet · commit 092b27a6d017 · 2021-11-23T21:23:28.000+01:00
Disable futility pruning at former PV nodes stored in the transposition table. STC: LLR: 2.96 (-2.94,2.94) <0.00,2.50> Total: 102256 W: 25708 L: 25318 D: 51230 Ptnml(0-2): 276, 11511, 27168, 11893, 280 https://tests.stockfishchess.org/tests/view/61990b3135c7c6348cb602db LTC: LLR: 2.96 (-2.94,2.94) <0.50,3.00> Total: 183304 W: 46027 L: 45408 D: 91869 Ptnml(0-2): 96, 19029, 52778, 19658, 91 https://tests.stockfishchess.org/tests/view/619a0d1b35c7c6348cb603bc closes #3804 Bench: 7334766
diff --git a/src/search.cpp b/src/search.cpp
@@ -817,7 +817,7 @@ namespace {
 
     // Step 7. Futility pruning: child node (~50 Elo).
     // The depth condition is important for mate finding.
-    if (   !PvNode
+    if (   !ss->ttPv
         &&  depth < 9
         &&  eval - futility_margin(depth, improving) >= beta
         &&  eval < 15000) // 50% larger than VALUE_KNOWN_WIN, but smaller than TB wins.
