Tune FRC trapped Bishop patch

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 58dd0026fdd1e94006b062b4ec3bb97ba4a6dcd1..a5c049a88adb8446cb14720a51b3ab109effa45d 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -1,6 +1,6 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
-  Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
+  Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -61,7 +61,7 @@ namespace Stockfish {
 namespace Eval {
 
   bool useNNUE;
-  string eval_file_loaded = "None";
+  string currentEvalFileName = "None";
 
   /// NNUE::init() tries to load a NNUE network at startup time, or when the engine
   /// receives a UCI command "setoption name EvalFile value nn-[a-z0-9]{12}.nnue"
@@ -90,13 +90,13 @@ namespace Eval {
     #endif
 
     for (string directory : dirs)
-        if (eval_file_loaded != eval_file)
+        if (currentEvalFileName != eval_file)
         {
             if (directory != "<internal>")
             {
                 ifstream stream(directory + eval_file, ios::binary);
                 if (load_eval(eval_file, stream))
-                    eval_file_loaded = eval_file;
+                    currentEvalFileName = eval_file;
             }
 
             if (directory == "<internal>" && eval_file == EvalFileDefaultName)
@@ -111,7 +111,7 @@ namespace Eval {
 
                 istream stream(&buffer);
                 if (load_eval(eval_file, stream))
-                    eval_file_loaded = eval_file;
+                    currentEvalFileName = eval_file;
             }
         }
   }
@@ -123,7 +123,7 @@ namespace Eval {
     if (eval_file.empty())
         eval_file = EvalFileDefaultName;
 
-    if (useNNUE && eval_file_loaded != eval_file)
+    if (useNNUE && currentEvalFileName != eval_file)
     {
 
         string msg1 = "If the UCI option \"Use NNUE\" is set to true, network evaluation parameters compatible with the engine must be available.";
@@ -192,8 +192,8 @@ using namespace Trace;
 namespace {
 
   // Threshold for lazy and space evaluation
-  constexpr Value LazyThreshold1    =  Value(3130);
-  constexpr Value LazyThreshold2    =  Value(2204);
+  constexpr Value LazyThreshold1    =  Value(3631);
+  constexpr Value LazyThreshold2    =  Value(2084);
   constexpr Value SpaceThreshold    =  Value(11551);
 
   // KingAttackWeights[PieceType] contains king attack weights by piece type
@@ -988,7 +988,9 @@ namespace {
 
     // Early exit if score is high
     auto lazy_skip = [&](Value lazyThreshold) {
-        return abs(mg_value(score) + eg_value(score)) > lazyThreshold + pos.non_pawn_material() / 32;
+        return abs(mg_value(score) + eg_value(score)) >   lazyThreshold
+                                                        + std::abs(pos.this_thread()->bestValue) * 5 / 4
+                                                        + pos.non_pawn_material() / 32;
     };
 
     if (lazy_skip(LazyThreshold1))
@@ -1067,8 +1069,8 @@ make_v:
         && pos.piece_on(SQ_G7) == B_PAWN)
         correction += CorneredBishop;
 
-    return pos.side_to_move() == WHITE ?  Value(5 * correction)
-                                       : -Value(5 * correction);
+    return pos.side_to_move() == WHITE ?  Value(3 * correction)
+                                       : -Value(3 * correction);
   }
 
 } // namespace Eval
@@ -1080,38 +1082,36 @@ make_v:
 Value Eval::evaluate(const Position& pos) {
 
   Value v;
+  bool useClassical = false;
 
-  if (!Eval::useNNUE)
-      v = Evaluation<NO_TRACE>(pos).value();
-  else
+  // Deciding between classical and NNUE eval (~10 Elo): for high PSQ imbalance we use classical,
+  // but we switch to NNUE during long shuffling or with high material on the board.
+  if (  !useNNUE
+      || abs(eg_value(pos.psq_score())) * 5 > (849 + pos.non_pawn_material() / 64) * (5 + pos.rule50_count()))
   {
-      // Scale and shift NNUE for compatibility with search and classical evaluation
-      auto  adjusted_NNUE = [&]()
-      {
-         int scale =   883
-                     + 32 * pos.count<PAWN>()
-                     + 32 * pos.non_pawn_material() / 1024;
-
-         Value nnue = NNUE::evaluate(pos, true) * scale / 1024;
-
-         if (pos.is_chess960())
-             nnue += fix_FRC(pos);
-
-         return nnue;
-      };
-
-      // If there is PSQ imbalance we use the classical eval, but we switch to
-      // NNUE eval faster when shuffling or if the material on the board is high.
-      int r50 = pos.rule50_count();
-      Value psq = Value(abs(eg_value(pos.psq_score())));
-      bool classical = psq * 5 > (850 + pos.non_pawn_material() / 64) * (5 + r50);
+      v = Evaluation<NO_TRACE>(pos).value();          // classical
+      useClassical = abs(v) >= 298;
+  }
 
-      v = classical ? Evaluation<NO_TRACE>(pos).value()  // classical
-                    : adjusted_NNUE();                   // NNUE
+  // If result of a classical evaluation is much lower than threshold fall back to NNUE
+  if (useNNUE && !useClassical)
+  {
+       Value nnue     = NNUE::evaluate(pos, true);     // NNUE
+       int scale      = 1136 + 20 * pos.non_pawn_material() / 1024;
+       Color stm      = pos.side_to_move();
+       Value optimism = pos.this_thread()->optimism[stm];
+       Value psq      = (stm == WHITE ? 1 : -1) * eg_value(pos.psq_score());
+       int complexity = 35 * abs(nnue - psq) / 256;
+
+       optimism = optimism * (44 + complexity) / 32;
+       v = (nnue + optimism) * scale / 1024 - optimism;
+
+       if (pos.is_chess960())
+           v += fix_FRC(pos);
   }
 
   // Damp down the evaluation linearly when shuffling
-  v = v * (100 - pos.rule50_count()) / 100;
+  v = v * (208 - pos.rule50_count()) / 208;
 
   // Guarantee evaluation does not hit the tablebase range
   v = std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
@@ -1136,7 +1136,11 @@ std::string Eval::trace(Position& pos) {
 
   std::memset(scores, 0, sizeof(scores));
 
-  pos.this_thread()->trend = SCORE_ZERO; // Reset any dynamic contempt
+  // Reset any global variable used in eval
+  pos.this_thread()->trend           = SCORE_ZERO;
+  pos.this_thread()->bestValue       = VALUE_ZERO;
+  pos.this_thread()->optimism[WHITE] = VALUE_ZERO;
+  pos.this_thread()->optimism[BLACK] = VALUE_ZERO;
 
   v = Evaluation<TRACE>(pos).value();