X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fevaluate.cpp;h=0fb9abdf2404ff3a6edc775238c885e1b129f604;hb=6ad4f485d37556f5e09baae5a939f44ac5b51c84;hp=789e28594cd6d8f2a7c555750b165903088f1afd;hpb=f40913f7f699d9d875e44929608b45947421ad03;p=stockfish

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 789e2859..0fb9abdf 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -33,6 +33,7 @@
 #include "misc.h"
 #include "pawns.h"
 #include "thread.h"
+#include "timeman.h"
 #include "uci.h"
 #include "incbin/incbin.h"
 
@@ -1096,7 +1097,7 @@ Value Eval::evaluate(const Position& pos) {
                     + material / 32
                     - 4 * pos.rule50_count();
 
-         Value nnue = NNUE::evaluate(pos) * scale / 1024 + Tempo;
+         Value nnue = NNUE::evaluate(pos) * scale / 1024 + Time.tempoNNUE;
 
          if (pos.is_chess960())
              nnue += fix_FRC(pos);
@@ -1104,23 +1105,26 @@ Value Eval::evaluate(const Position& pos) {
          return nnue;
       };
 
-      // If there is PSQ imbalance use classical eval, with small probability if it is small
+      // If there is PSQ imbalance we use the classical eval. We also introduce
+      // a small probability of using the classical eval when PSQ imbalance 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));
 
       // Use classical evaluation for really low piece endgames.
-      // The most critical case is a bishop + A/H file pawn vs naked king draw.
-      bool strongClassical = pos.non_pawn_material() < 2 * RookValueMg && pos.count<PAWN>() < 2;
+      // One critical case is the draw for bishop + A/H file pawn vs naked king.
+      bool lowPieceEndgame =   pos.non_pawn_material() == BishopValueMg
+                            || (pos.non_pawn_material() < 2 * RookValueMg && pos.count<PAWN>() < 2);
 
-      v = classical || strongClassical ? Evaluation<NO_TRACE>(pos).value() : adjusted_NNUE();
+      v = classical || lowPieceEndgame ? 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
-          && !strongClassical
+      // 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
+          && !lowPieceEndgame
           && (   abs(v) * 16 < NNUEThreshold2 * r50
               || (   pos.opposite_bishops()
                   && abs(v) * 16 < (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50