Improve the Chess960 correction for cornered bishops

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index f9754795603bd413b38cce6a565d2e23777426b8..58dd0026fdd1e94006b062b4ec3bb97ba4a6dcd1 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -78,6 +78,8 @@ namespace Eval {
         return;
 
     string eval_file = string(Options["EvalFile"]);
+    if (eval_file.empty())
+        eval_file = EvalFileDefaultName;
 
     #if defined(DEFAULT_NNUE_DIRECTORY)
     #define stringify2(x) #x
@@ -118,16 +120,16 @@ namespace Eval {
   void NNUE::verify() {
 
     string eval_file = string(Options["EvalFile"]);
+    if (eval_file.empty())
+        eval_file = EvalFileDefaultName;
 
     if (useNNUE && eval_file_loaded != eval_file)
     {
-        UCI::OptionsMap defaults;
-        UCI::init(defaults);
 
         string msg1 = "If the UCI option \"Use NNUE\" is set to true, network evaluation parameters compatible with the engine must be available.";
         string msg2 = "The option is set to true, but the network file " + eval_file + " was not loaded successfully.";
         string msg3 = "The UCI option EvalFile might need to specify the full path, including the directory name, to the network file.";
-        string msg4 = "The default net can be downloaded from: https://tests.stockfishchess.org/api/nn/" + string(defaults["EvalFile"]);
+        string msg4 = "The default net can be downloaded from: https://tests.stockfishchess.org/api/nn/" + std::string(EvalFileDefaultName);
         string msg5 = "The engine will be terminated now.";
 
         sync_cout << "info string ERROR: " << msg1 << sync_endl;
@@ -190,8 +192,8 @@ using namespace Trace;
 namespace {
 
   // Threshold for lazy and space evaluation
-  constexpr Value LazyThreshold1    =  Value(1565);
-  constexpr Value LazyThreshold2    =  Value(1102);
+  constexpr Value LazyThreshold1    =  Value(3130);
+  constexpr Value LazyThreshold2    =  Value(2204);
   constexpr Value SpaceThreshold    =  Value(11551);
 
   // KingAttackWeights[PieceType] contains king attack weights by piece type
@@ -986,7 +988,7 @@ namespace {
 
     // Early exit if score is high
     auto lazy_skip = [&](Value lazyThreshold) {
-        return abs(mg_value(score) + eg_value(score)) / 2 > lazyThreshold + pos.non_pawn_material() / 64;
+        return abs(mg_value(score) + eg_value(score)) > lazyThreshold + pos.non_pawn_material() / 32;
     };
 
     if (lazy_skip(LazyThreshold1))
@@ -1051,26 +1053,22 @@ make_v:
 
     if (   pos.piece_on(SQ_A1) == W_BISHOP
         && pos.piece_on(SQ_B2) == W_PAWN)
-        correction += !pos.empty(SQ_B3) ? -CorneredBishop * 4
-                                        : -CorneredBishop * 3;
+        correction -= CorneredBishop;
 
     if (   pos.piece_on(SQ_H1) == W_BISHOP
         && pos.piece_on(SQ_G2) == W_PAWN)
-        correction += !pos.empty(SQ_G3) ? -CorneredBishop * 4
-                                        : -CorneredBishop * 3;
+        correction -= CorneredBishop;
 
     if (   pos.piece_on(SQ_A8) == B_BISHOP
         && pos.piece_on(SQ_B7) == B_PAWN)
-        correction += !pos.empty(SQ_B6) ? CorneredBishop * 4
-                                        : CorneredBishop * 3;
+        correction += CorneredBishop;
 
     if (   pos.piece_on(SQ_H8) == B_BISHOP
         && pos.piece_on(SQ_G7) == B_PAWN)
-        correction += !pos.empty(SQ_G6) ? CorneredBishop * 4
-                                        : CorneredBishop * 3;
+        correction += CorneredBishop;
 
-    return pos.side_to_move() == WHITE ?  Value(correction)
-                                       : -Value(correction);
+    return pos.side_to_move() == WHITE ?  Value(5 * correction)
+                                       : -Value(5 * correction);
   }
 
 } // namespace Eval
@@ -1090,7 +1088,7 @@ Value Eval::evaluate(const Position& pos) {
       // Scale and shift NNUE for compatibility with search and classical evaluation
       auto  adjusted_NNUE = [&]()
       {
-         int scale =   903
+         int scale =   883
                      + 32 * pos.count<PAWN>()
                      + 32 * pos.non_pawn_material() / 1024;
 
@@ -1106,7 +1104,7 @@ Value Eval::evaluate(const Position& pos) {
       // 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 > (750 + pos.non_pawn_material() / 64) * (5 + r50);
+      bool classical = psq * 5 > (850 + pos.non_pawn_material() / 64) * (5 + r50);
 
       v = classical ? Evaluation<NO_TRACE>(pos).value()  // classical
                     : adjusted_NNUE();                   // NNUE