Simplify EVASIONS scoring

remove some multipliers & adjust, doesn't change the move ordering

STC https://tests.stockfishchess.org/tests/view/6325c1c9b9c0caa5f4a759ae
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 192760 W: 51528 L: 51482 D: 89750
Ptnml(0-2): 642, 20490, 54148, 20380, 720

Credit to locutus2

closes https://github.com/official-stockfish/Stockfish/pull/4171

No functional change

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 636f4ba7987a90113c409bf0df35961a88574769..e10454b0d982c9e68df1e89ccafb7c05c73c7962 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -145,11 +145,11 @@ void MovePicker::score() {
       {
           if (pos.capture(m))
               m.value =  PieceValue[MG][pos.piece_on(to_sq(m))]
-                       - Value(type_of(pos.moved_piece(m)));
+                       - Value(type_of(pos.moved_piece(m)))
+                       + (1 << 28);
           else
-              m.value =  2 * (*mainHistory)[pos.side_to_move()][from_to(m)]
-                       + 2 * (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)]
-                       - (1 << 28);
+              m.value =  (*mainHistory)[pos.side_to_move()][from_to(m)]
+                       + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)];
       }
 }