Quantize eval to multiples of 16

vondele · snicolet · commit 4d657618e956 · 2020-06-13T07:10:34.000+02:00
Removes some excess precision, helps searchs. Effectively reintroduces evaluation grain, with a slightly different context. 45dbd9c passed STC LLR: 2.97 (-2.94,2.94) {-0.50,1.50} Total: 197032 W: 37938 L: 37462 D: 121632 Ptnml(0-2): 3359, 22994, 45446, 23246, 3471 https://tests.stockfishchess.org/tests/view/5ee0c228f29b40b0fc95ae53 passed LTC LLR: 2.94 (-2.94,2.94) {0.25,1.75} Total: 77696 W: 9970 L: 9581 D: 58145 Ptnml(0-2): 530, 7075, 23311, 7340, 592 https://tests.stockfishchess.org/tests/view/5ee21426f29b40b0fc95af43 passed LTC SMP LLR: 2.96 (-2.94,2.94) {0.25,1.75} Total: 64136 W: 7425 L: 7091 D: 49620 Ptnml(0-2): 345, 5416, 20228, 5718, 361 https://tests.stockfishchess.org/tests/view/5ee387bbf29b40b0fc95b04c closes #2733 Bench: 4939103
diff --git a/src/evaluate.cpp b/src/evaluate.cpp
@@ -855,6 +855,9 @@ namespace {
         Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
     }
 
+    // Evaluation grain
+    v = (v / 16) * 16;
+
     // Side to move point of view
     v = (pos.side_to_move() == WHITE ? v : -v) + Tempo;
 

Original file line number	Diff line number	Diff line change
`@@ -855,6 +855,9 @@ namespace {`
`855`	`855`	`Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);`
`856`	`856`	`}`
`857`	`857`
	`858`	`+ // Evaluation grain`
	`859`	`+ v = (v / 16) * 16;`
	`860`	`+`
`858`	`861`	`// Side to move point of view`
`859`	`862`	`v = (pos.side_to_move() == WHITE ? v : -v) + Tempo;`
`860`	`863`