Simplify use of low-ply history in evasions

xu-shawn · vondele · commit 3073d82ccf25 · 2025-09-28T21:21:57.000+02:00
Passed Non-regression STC: LLR: 2.95 (-2.94,2.94) <-1.75,0.25> Total: 65024 W: 16991 L: 16804 D: 31229 Ptnml(0-2): 182, 7423, 17119, 7602, 186 https://tests.stockfishchess.org/tests/view/68c23f5459efc3c96b6113df Passed Non-regression LTC: LLR: 2.96 (-2.94,2.94) <-1.75,0.25> Total: 207312 W: 53126 L: 53095 D: 101091 Ptnml(0-2): 126, 21986, 59389, 22041, 114 https://tests.stockfishchess.org/tests/view/68c241e359efc3c96b6113ef closes #6308 Bench: 2515619
diff --git a/src/movepick.cpp b/src/movepick.cpp
@@ -188,7 +188,7 @@ ExtMove* MovePicker::score(MoveList<Type>& ml) {
             {
                 m.value = (*mainHistory)[us][m.from_to()] + (*continuationHistory[0])[pc][to];
                 if (ply < LOW_PLY_HISTORY_SIZE)
-                    m.value += 2 * (*lowPlyHistory)[ply][m.from_to()] / (1 + ply);
+                    m.value += 2 * (*lowPlyHistory)[ply][m.from_to()];
             }
         }
     }

Original file line number	Diff line number	Diff line change
`@@ -188,7 +188,7 @@ ExtMove* MovePicker::score(MoveList<Type>& ml) {`
`188`	`188`	`{`
`189`	`189`	`m.value = (mainHistory)[us][m.from_to()] + (continuationHistory[0])[pc][to];`
`190`	`190`	`if (ply < LOW_PLY_HISTORY_SIZE)`
`191`		`- m.value += 2 * (*lowPlyHistory)[ply][m.from_to()] / (1 + ply);`
	`191`	`+ m.value += 2 * (*lowPlyHistory)[ply][m.from_to()];`
`192`	`192`	`}`
`193`	`193`	`}`
`194`	`194`	`}`