Skip LMR for 2nd move at the root only

TarasVuk · Disservin · commit 85403a89bac9 · 2023-12-02T11:41:31.000+01:00
This patch reverts commit by Vizvezdenec: 27139de Passed STC: https://tests.stockfishchess.org/tests/view/65660b4a136acbc57354f13d LLR: 2.94 (-2.94,2.94) <-1.75,0.25> Total: 301952 W: 76271 L: 76344 D: 149337 Ptnml(0-2): 1053, 36293, 76348, 36238, 1044 Passed LTC: https://tests.stockfishchess.org/tests/view/656738ab136acbc573550e39 LLR: 2.94 (-2.94,2.94) <-1.75,0.25> Total: 25050 W: 6283 L: 6063 D: 12704 Ptnml(0-2): 10, 2756, 6775, 2972, 12 closes #4895 Bench: 1722961
diff --git a/src/search.cpp b/src/search.cpp
@@ -1171,7 +1171,7 @@ Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, boo
         // 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
         // cases where we extend a son if it has good chances to be "interesting".
-        if (depth >= 2 && moveCount > 1 + (PvNode && ss->ply <= 1)
+        if (depth >= 2 && moveCount > 1 + rootNode
             && (!ss->ttPv || !capture || (cutNode && (ss - 1)->moveCount > 1)))
         {
             // In general we want to cap the LMR depth search at newDepth, but when

Original file line number	Diff line number	Diff line change
`@@ -1171,7 +1171,7 @@ Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, boo`
`1171`	`1171`	`// We use various heuristics for the sons of a node after the first son has`
`1172`	`1172`	`// been searched. In general, we would like to reduce them, but there are many`
`1173`	`1173`	`// cases where we extend a son if it has good chances to be "interesting".`
`1174`		`- if (depth >= 2 && moveCount > 1 + (PvNode && ss->ply <= 1)`
	`1174`	`+ if (depth >= 2 && moveCount > 1 + rootNode`
`1175`	`1175`	`&& (!ss->ttPv \|\| !capture \|\| (cutNode && (ss - 1)->moveCount > 1)))`
`1176`	`1176`	`{`
`1177`	`1177`	`// In general we want to cap the LMR depth search at newDepth, but when`