]> git.sesse.net Git - stockfish/blobdiff - src/evaluate.cpp
Small clean-ups
[stockfish] / src / evaluate.cpp
index bb4f9ef7f44ba53892773959b7f8b862de3beeed..403d59dd70d0cc0deb1b5f6f69433ff784a9ba44 100644 (file)
@@ -33,6 +33,7 @@
 #include "misc.h"
 #include "pawns.h"
 #include "thread.h"
+#include "timeman.h"
 #include "uci.h"
 #include "incbin/incbin.h"
 
@@ -54,7 +55,6 @@
 
 
 using namespace std;
-using namespace Stockfish::Eval::NNUE;
 
 namespace Stockfish {
 
@@ -114,6 +114,30 @@ namespace Eval {
         }
   }
 
+  /// NNUE::export_net() exports the currently loaded network to a file
+  void NNUE::export_net(const std::optional<std::string>& filename) {
+    std::string actualFilename;
+
+    if (filename.has_value())
+        actualFilename = filename.value();
+    else 
+    {
+        if (eval_file_loaded != EvalFileDefaultName)
+        {
+             sync_cout << "Failed to export a net. A non-embedded net can only be saved if the filename is specified." << sync_endl;
+             return;
+        }
+        actualFilename = EvalFileDefaultName;
+    }
+
+    ofstream stream(actualFilename, std::ios_base::binary);
+
+    if (save_eval(stream))
+        sync_cout << "Network saved successfully to " << actualFilename << "." << sync_endl;
+    else
+        sync_cout << "Failed to export a net." << sync_endl;
+  }
+
   /// NNUE::verify() verifies that the last net used was loaded successfully
   void NNUE::verify() {
 
@@ -257,11 +281,12 @@ namespace {
     S(0, 0), S(3, 44), S(37, 68), S(42, 60), S(0, 39), S(58, 43)
   };
 
+  constexpr Value CorneredBishop = Value(50);
+
   // Assorted bonuses and penalties
   constexpr Score UncontestedOutpost  = S(  1, 10);
   constexpr Score BishopOnKingRing    = S( 24,  0);
   constexpr Score BishopXRayPawns     = S(  4,  5);
-  constexpr Score CorneredBishop      = S( 50, 50);
   constexpr Score FlankAttacks        = S(  8,  0);
   constexpr Score Hanging             = S( 69, 36);
   constexpr Score KnightOnQueen       = S( 16, 11);
@@ -396,8 +421,9 @@ namespace {
 
     attackedBy[Us][Pt] = 0;
 
-    while (b1) {
-        Square s = pop_lsb(&b1);
+    while (b1)
+    {
+        Square s = pop_lsb(b1);
 
         // Find attacked squares, including x-ray attacks for bishops and rooks
         b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
@@ -477,9 +503,8 @@ namespace {
                 {
                     Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
                     if (pos.piece_on(s + d) == make_piece(Us, PAWN))
-                        score -= !pos.empty(s + d + pawn_push(Us))                ? CorneredBishop * 4
-                                : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? CorneredBishop * 2
-                                                                                  : CorneredBishop;
+                        score -= !pos.empty(s + d + pawn_push(Us)) ? 4 * make_score(CorneredBishop, CorneredBishop)
+                                                                   : 3 * make_score(CorneredBishop, CorneredBishop);
                 }
             }
         }
@@ -658,11 +683,11 @@ namespace {
     {
         b = (defended | weak) & (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP]);
         while (b)
-            score += ThreatByMinor[type_of(pos.piece_on(pop_lsb(&b)))];
+            score += ThreatByMinor[type_of(pos.piece_on(pop_lsb(b)))];
 
         b = weak & attackedBy[Us][ROOK];
         while (b)
-            score += ThreatByRook[type_of(pos.piece_on(pop_lsb(&b)))];
+            score += ThreatByRook[type_of(pos.piece_on(pop_lsb(b)))];
 
         if (weak & attackedBy[Us][KING])
             score += ThreatByKing;
@@ -760,7 +785,7 @@ namespace {
 
     while (b)
     {
-        Square s = pop_lsb(&b);
+        Square s = pop_lsb(b);
 
         assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));
 
@@ -906,7 +931,7 @@ namespace {
     Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
     int sf = me->scale_factor(pos, strongSide);
 
-    // If scale factor is not already specific, scale down via general heuristics
+    // If scale factor is not already specific, scale up/down via general heuristics
     if (sf == SCALE_FACTOR_NORMAL)
     {
         if (pos.opposite_bishops())
@@ -1038,46 +1063,43 @@ make_v:
     return v;
   }
 
-  // specifically correct for cornered bishops to fix FRC with NNUE.
+
+  /// Fisher Random Chess: correction for cornered bishops, to fix chess960 play with NNUE
+
   Value fix_FRC(const Position& pos) {
 
-    Value bAdjust = Value(0);
+    constexpr Bitboard Corners =  1ULL << SQ_A1 | 1ULL << SQ_H1 | 1ULL << SQ_A8 | 1ULL << SQ_H8;
 
-    constexpr Value p1=Value(209), p2=Value(136), p3=Value(148);
+    if (!(pos.pieces(BISHOP) & Corners))
+        return VALUE_ZERO;
 
-    Color Us = pos.side_to_move();
-    if (   (pos.pieces(Us, BISHOP) & relative_square(Us, SQ_A1))
-        && (pos.pieces(Us, PAWN) & relative_square(Us, SQ_B2)))
-    {
-        bAdjust      -= !pos.empty(relative_square(Us,SQ_B3))                            ? p1
-                       : pos.piece_on(relative_square(Us,SQ_C3)) == make_piece(Us, PAWN) ? p2
-                                                                                         : p3;
-    }
-    if (   (pos.pieces(Us, BISHOP) & relative_square(Us, SQ_H1))
-        && (pos.pieces(Us, PAWN) & relative_square(Us, SQ_G2)))
-    {
-        bAdjust      -= !pos.empty(relative_square(Us,SQ_G3))                            ? p1
-                       : pos.piece_on(relative_square(Us,SQ_F3)) == make_piece(Us, PAWN) ? p2
-                                                                                         : p3;
-    }
-    if (   (pos.pieces(~Us, BISHOP) & relative_square(Us, SQ_A8))
-        && (pos.pieces(~Us, PAWN) & relative_square(Us, SQ_B7)))
-    {
-        bAdjust      += !pos.empty(relative_square(Us,SQ_B6))                             ? p1
-                       : pos.piece_on(relative_square(Us,SQ_C6)) == make_piece(~Us, PAWN) ? p2
-                                                                                          : p3;
-    }
-    if (   (pos.pieces(~Us, BISHOP) & relative_square(Us, SQ_H8))
-        && (pos.pieces(~Us, PAWN) & relative_square(Us, SQ_G7)))
-    {
-        bAdjust      += !pos.empty(relative_square(Us,SQ_G6))                             ? p1
-                       : pos.piece_on(relative_square(Us,SQ_F6)) == make_piece(~Us, PAWN) ? p2
-                                                                                          : p3;
-    }
-    return bAdjust;
+    int correction = 0;
+
+    if (   pos.piece_on(SQ_A1) == W_BISHOP
+        && pos.piece_on(SQ_B2) == W_PAWN)
+        correction += !pos.empty(SQ_B3) ? -CorneredBishop * 4
+                                        : -CorneredBishop * 3;
+
+    if (   pos.piece_on(SQ_H1) == W_BISHOP
+        && pos.piece_on(SQ_G2) == W_PAWN)
+        correction += !pos.empty(SQ_G3) ? -CorneredBishop * 4
+                                        : -CorneredBishop * 3;
+
+    if (   pos.piece_on(SQ_A8) == B_BISHOP
+        && pos.piece_on(SQ_B7) == B_PAWN)
+        correction += !pos.empty(SQ_B6) ? CorneredBishop * 4
+                                        : CorneredBishop * 3;
+
+    if (   pos.piece_on(SQ_H8) == B_BISHOP
+        && pos.piece_on(SQ_G7) == B_PAWN)
+        correction += !pos.empty(SQ_G6) ? CorneredBishop * 4
+                                        : CorneredBishop * 3;
+
+    return pos.side_to_move() == WHITE ?  Value(correction)
+                                       : -Value(correction);
   }
 
-} // namespace
+} // namespace Eval
 
 
 /// evaluate() is the evaluator for the outer world. It returns a static
@@ -1092,32 +1114,41 @@ Value Eval::evaluate(const Position& pos) {
   else
   {
       // Scale and shift NNUE for compatibility with search and classical evaluation
-      auto  adjusted_NNUE = [&](){
-         int mat = pos.non_pawn_material() + 2 * PawnValueMg * pos.count<PAWN>();
-         Value nnueValue = NNUE::evaluate(pos) * (641 + mat / 32 - 4 * pos.rule50_count()) / 1024 + Tempo;
+      auto  adjusted_NNUE = [&]()
+      {
+         int material = pos.non_pawn_material() + 4 * PawnValueMg * pos.count<PAWN>();
+         int scale =  580
+                    + material / 32
+                    - 4 * pos.rule50_count();
+
+         Value nnue = NNUE::evaluate(pos) * scale / 1024 + Time.tempoNNUE;
 
          if (pos.is_chess960())
-            nnueValue += fix_FRC(pos);
+             nnue += fix_FRC(pos);
 
-         return nnueValue;
+         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