+ if (!Eval::useNNUE)
+ v = Evaluation<NO_TRACE>(pos).value();
+ else
+ {
+ // Scale and shift NNUE for compatibility with search and classical evaluation
+ auto adjusted_NNUE = [&](){
+ int mat = pos.non_pawn_material();
+ return NNUE::evaluate(pos) * (1024 + mat / 32) / 1024 + Tempo;
+ };
+
+ // If there is PSQ imbalance use classical eval, with small probability if it is small
+ Value psq = Value(abs(eg_value(pos.psq_score())));
+ int r50 = 16 + pos.rule50_count();
+ bool largePsq = psq * 16 > (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50;
+ bool classical = largePsq || (psq > PawnValueMg / 4 && !(pos.this_thread()->nodes & 0xB));
+
+ v = classical ? Evaluation<NO_TRACE>(pos).value() : adjusted_NNUE();
+
+ // If the classical eval is small and imbalance large, use NNUE nevertheless.
+ // For the case of opposite colored bishops, switch to NNUE eval with
+ // small probability if the classical eval is less than the threshold.
+ if ( largePsq
+ && (abs(v) * 16 < NNUEThreshold2 * r50
+ || ( pos.opposite_bishops()
+ && abs(v) * 16 < (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50
+ && !(pos.this_thread()->nodes & 0xB))))
+ v = adjusted_NNUE();
+ }