Do not use lazy evaluation inside NNUE

[stockfish] / src / nnue / evaluate_nnue.cpp

diff --git a/src/nnue/evaluate_nnue.cpp b/src/nnue/evaluate_nnue.cpp
index 97cef81480fa8033525c2ce05eaf5eb495a675f7..4a3c206b8087fcb065ad0b9c4e595c68495701a8 100644 (file)
--- a/src/nnue/evaluate_nnue.cpp
+++ b/src/nnue/evaluate_nnue.cpp
@@ -134,7 +134,7 @@ namespace Stockfish::Eval::NNUE {
   }
 
   // Evaluation function. Perform differential calculation.
-  Value evaluate(const Position& pos) {
+  Value evaluate(const Position& pos, bool adjusted) {
 
     // We manually align the arrays on the stack because with gcc < 9.3
     // overaligning stack variables with alignas() doesn't work correctly.
@@ -158,14 +158,21 @@ namespace Stockfish::Eval::NNUE {
     ASSERT_ALIGNED(buffer, alignment);
 
     const std::size_t bucket = (pos.count<ALL_PIECES>() - 1) / 4;
+    const auto psqt = featureTransformer->transform(pos, transformedFeatures, bucket);
+    const auto output = network[bucket]->propagate(transformedFeatures, buffer);
 
-    const auto [psqt, lazy] = featureTransformer->transform(pos, transformedFeatures, bucket);
-    if (lazy) {
-      return static_cast<Value>(psqt / OutputScale);
-    } else {
-      const auto output = network[bucket]->propagate(transformedFeatures, buffer);
-      return static_cast<Value>((output[0] + psqt) / OutputScale);
-    }
+    int materialist = psqt;
+    int positional  = output[0];
+
+    int delta_npm = abs(pos.non_pawn_material(WHITE) - pos.non_pawn_material(BLACK));
+    int entertainment = (adjusted && delta_npm <= BishopValueMg - KnightValueMg ? 7 : 0);
+
+    int A = 128 - entertainment;
+    int B = 128 + entertainment;
+
+    int sum = (A * materialist + B * positional) / 128;
+
+    return static_cast<Value>( sum / OutputScale );
   }
 
   // Load eval, from a file stream or a memory stream