Remove NNUE scaling term

remove pawns scaling, probably correlated with piece scaling, and might be less useful with the recent improved nets. Might allow for another tune of the scaling params.

passed STC
https://tests.stockfishchess.org/tests/view/61afdb2e56fcf33bce7df31a
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 280864 W: 72198 L: 72399 D: 136267
Ptnml(0-2): 854, 32356, 74346, 31889, 987

passed LTC
https://tests.stockfishchess.org/tests/view/61b233a606b4c2dcb1b16140
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 400136 W: 102669 L: 103012 D: 194455
Ptnml(0-2): 212, 42005, 116047, 41522, 282

closes https://github.com/official-stockfish/Stockfish/pull/3851

Bench: 4735679

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 1dc701cfe0977f86cf39d42f3c4779d4c37c7009..24445f48292b9e6c7f584d3874ff1ecf45dd6a71 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -1091,8 +1091,7 @@ Value Eval::evaluate(const Position& pos) {
       v = Evaluation<NO_TRACE>(pos).value();          // classical
   else
   {
-       int scale = 1049
-                   +  8 * pos.count<PAWN>()
+       int scale = 1136
                    + 20 * pos.non_pawn_material() / 1024;
 
        Value nnue     = NNUE::evaluate(pos, true);     // NNUE