WebSVN – Games.Chess Giants – Diff – //engine-stockfish/evaluate.cpp

   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 #include "evaluate.h"
 #include "material.h"
 #include "pawns.h"
 namespace {
+  const Bitboard Center      = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
+  const Bitboard QueenSide   = FileABB | FileBBB | FileCBB | FileDBB;
+  const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
+  const Bitboard KingSide    = FileEBB | FileFBB | FileGBB | FileHBB;
+  const Bitboard KingFlank[FILE_NB] = {
+    QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide
+  };
   namespace Trace {
+    enum Tracing {NO_TRACE, TRACE};
     enum Term { // The first 8 entries are for PieceType
-      MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB
+      MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, INITIATIVE, TOTAL, TERM_NB
     };
     double scores[TERM_NB][COLOR_NB][PHASE_NB];
     double to_cp(Value v) { return double(v) / PawnValueEg; }
       add(idx, WHITE, w); add(idx, BLACK, b);
+    }
     std::ostream& operator<<(std::ostream& os, Term t) {
-      if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL)
+      if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == INITIATIVE || t == TOTAL)
           os << "  ---   --- |   ---   --- | ";
       else
           os << std::setw(5) << scores[t][WHITE][MG] << " "
              << std::setw(5) << scores[t][WHITE][EG] << " | "
              << std::setw(5) << scores[t][BLACK][MG] << " "
+    }
+  }
   using namespace Trace;
-  // Struct EvalInfo contains various information computed and collected
+  // Evaluation class contains various information computed and collected
   // by the evaluation functions.
+  template<Tracing T = NO_TRACE>
-  struct EvalInfo {
+  class Evaluation {
+  public:
+    Evaluation() = delete;
+    Evaluation(const Position& p) : pos(p) {}
+    Evaluation& operator=(const Evaluation&) = delete;
+    Value value();
+  private:
+    // Evaluation helpers (used when calling value())
+    template<Color Us> void initialize();
+    template<Color Us> Score evaluate_king();
+    template<Color Us> Score evaluate_threats();
+    int king_distance(Color c, Square s);
+    template<Color Us> Score evaluate_passed_pawns();
+    template<Color Us> Score evaluate_space();
+    template<Color Us, PieceType Pt> Score evaluate_pieces();
+    ScaleFactor evaluate_scale_factor(Value eg);
+    Score evaluate_initiative(Value eg);
+    // Data members
+    const Position& pos;
+    Material::Entry* me;
+    Pawns::Entry* pe;
+    Bitboard mobilityArea[COLOR_NB];
+    Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO };
     // attackedBy[color][piece type] is a bitboard representing all squares
-    // attacked by a given color and piece type (can be also ALL_PIECES).
+    // attacked by a given color and piece type. Special "piece types" which are
+    // also calculated are QUEEN_DIAGONAL and ALL_PIECES.
     Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
     // attackedBy2[color] are the squares attacked by 2 pieces of a given color,
     // possibly via x-ray or by one pawn and one piece. Diagonal x-ray through
     // pawn or squares attacked by 2 pawns are not explicitly added.
     Bitboard attackedBy2[COLOR_NB];
     // kingRing[color] is the zone around the king which is considered
     // by the king safety evaluation. This consists of the squares directly
-    // adjacent to the king, and the three (or two, for a king on an edge file)
+    // adjacent to the king, and (only for a king on its first rank) the
     // squares two ranks in front of the king. For instance, if black's king
     // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8,
     // f7, g7, h7, f6, g6 and h6.
     Bitboard kingRing[COLOR_NB];
     // color to squares directly adjacent to the enemy king. Pieces which attack
     // more than one square are counted multiple times. For instance, if there is
     // a white knight on g5 and black's king is on g8, this white knight adds 2
     // to kingAdjacentZoneAttacksCount[WHITE].
     int kingAdjacentZoneAttacksCount[COLOR_NB];
-    Bitboard pinnedPieces[COLOR_NB];
-    Material::Entry* me;
-    Pawns::Entry* pi;
   };
   #define V(v) Value(v)
   #define S(mg, eg) make_score(mg, eg)
-  // MobilityBonus[PieceType][attacked] contains bonuses for middle and end
+  // MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game,
-  // game, indexed by piece type and number of attacked squares in the MobilityArea.
+  // indexed by piece type and number of attacked squares in the mobility area.
   const Score MobilityBonus[][32] = {
-    {}, {},
-    { S(-75,-76), S(-56,-54), S( -9,-26), S( -2,-10), S(  6,  5), S( 15, 11), // Knights
+    { S(-75,-76), S(-57,-54), S( -9,-28), S( -2,-10), S(  6,  5), S( 14, 12), // Knights
-      S( 22, 26), S( 30, 28), S( 36, 29) },
+      S( 22, 26), S( 29, 29), S( 36, 29) },
-    { S(-48,-58), S(-21,-19), S( 16, -2), S( 26, 12), S( 37, 22), S( 51, 42), // Bishops
+    { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishops
-      S( 54, 54), S( 63, 58), S( 65, 63), S( 71, 70), S( 79, 74), S( 81, 86),
+      S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86),
-      S( 92, 90), S( 97, 94) },
+      S( 91, 88), S( 98, 97) },
-    { S(-56,-78), S(-25,-18), S(-11, 26), S( -5, 55), S( -4, 70), S( -1, 81), // Rooks
+    { S(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rooks
-      S(  8,109), S( 14,120), S( 21,128), S( 23,143), S( 31,154), S( 32,160),
+      S(  9,112), S( 16,118), S( 30,132), S( 29,142), S( 32,155), S( 38,165),
-      S( 43,165), S( 49,168), S( 59,169) },
+      S( 46,166), S( 48,169), S( 58,171) },
-    { S(-40,-35), S(-25,-12), S(  2,  7), S(  4, 19), S( 14, 37), S( 24, 55), // Queens
+    { S(-39,-36), S(-21,-15), S(  3,  8), S(  3, 18), S( 14, 34), S( 22, 54), // Queens
-      S( 25, 62), S( 40, 76), S( 43, 79), S( 47, 87), S( 54, 94), S( 56,102),
+      S( 28, 61), S( 41, 73), S( 43, 79), S( 48, 92), S( 56, 94), S( 60,104),
-      S( 60,111), S( 70,116), S( 72,118), S( 73,122), S( 75,128), S( 77,130),
+      S( 60,113), S( 66,120), S( 67,123), S( 70,126), S( 71,133), S( 73,136),
-      S( 85,133), S( 94,136), S( 99,140), S(108,157), S(112,158), S(113,161),
+      S( 79,140), S( 88,143), S( 88,148), S( 99,166), S(102,170), S(102,175),
-      S(118,174), S(119,177), S(123,191), S(128,199) }
+      S(106,184), S(109,191), S(113,206), S(116,212) }
   };
-  // Outpost[knight/bishop][supported by pawn] contains bonuses for knights and
+  // Outpost[knight/bishop][supported by pawn] contains bonuses for minor
-  // bishops outposts, bigger if outpost piece is supported by a pawn.
+  // pieces if they can reach an outpost square, bigger if that square is
+  // supported by a pawn. If the minor piece occupies an outpost square
+  // then score is doubled.
   const Score Outpost[][2] = {
-    { S(43,11), S(65,20) }, // Knights
-    { S(20, 3), S(29, 8) }  // Bishops
-  };
-  // ReachableOutpost[knight/bishop][supported by pawn] contains bonuses for
-  // knights and bishops which can reach an outpost square in one move, bigger
-  // if outpost square is supported by a pawn.
-  const Score ReachableOutpost[][2] = {
-    { S(21, 5), S(35, 8) }, // Knights
+    { S(22, 6), S(36,12) }, // Knight
-    { S( 8, 0), S(14, 4) }  // Bishops
+    { S( 9, 2), S(15, 5) }  // Bishop
   };
   // RookOnFile[semiopen/open] contains bonuses for each rook when there is no
   // friendly pawn on the rook file.
-  const Score RookOnFile[2] = { S(20, 7), S(45, 20) };
+  const Score RookOnFile[] = { S(20, 7), S(45, 20) };
-  // ThreatBySafePawn[PieceType] contains bonuses according to which piece
+  // ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to
-  // type is attacked by a pawn which is protected or is not attacked.
+  // which piece type attacks which one. Attacks on lesser pieces which are
+  // pawn-defended are not considered.
-  const Score ThreatBySafePawn[PIECE_TYPE_NB] = {
+  const Score ThreatByMinor[PIECE_TYPE_NB] = {
-    S(0, 0), S(0, 0), S(176, 139), S(131, 127), S(217, 218), S(203, 215)
+    S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72, 107), S(48, 118)
   };
-  // Threat[by minor/by rook][attacked PieceType] contains
-  // bonuses according to which piece type attacks which one.
-  // Attacks on lesser pieces which are pawn-defended are not considered.
-  const Score Threat[][PIECE_TYPE_NB] = {
+  const Score ThreatByRook[PIECE_TYPE_NB] = {
-    { S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72,107), S(48,118) }, // by Minor
-    { S(0, 0), S(0, 25), S(40, 62), S(40, 59), S( 0, 34), S(35, 48) }  // by Rook
+    S(0, 0), S(0, 25), S(40, 62), S(40, 59), S(0, 34), S(35, 48)
   };
-  // ThreatByKing[on one/on many] contains bonuses for King attacks on
+  // ThreatByKing[on one/on many] contains bonuses for king attacks on
   // pawns or pieces which are not pawn-defended.
-  const Score ThreatByKing[2] = { S(3, 62), S(9, 138) };
+  const Score ThreatByKing[] = { S(3, 62), S(9, 138) };
   // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns.
   // We don't use a Score because we process the two components independently.
   const Value Passed[][RANK_NB] = {
-    { V(5), V( 5), V(31), V(73), V(166), V(252) },
+    { V(0), V(5), V( 5), V(31), V(73), V(166), V(252) },
-    { V(7), V(14), V(38), V(73), V(166), V(252) }
+    { V(0), V(7), V(14), V(38), V(73), V(166), V(252) }
   };
   // PassedFile[File] contains a bonus according to the file of a passed pawn
   const Score PassedFile[FILE_NB] = {
     S(  9, 10), S( 2, 10), S( 1, -8), S(-20,-12),
-    S(-20,-12), S( 1, -8), S( 2, 10), S( 9, 10)
+    S(-20,-12), S( 1, -8), S( 2, 10), S(  9, 10)
   };
-  // Assorted bonuses and penalties used by evaluation
+  // Rank factor applied on some bonus for passed pawn on rank 4 or beyond
-  const Score MinorBehindPawn     = S(16,  0);
-  const Score BishopPawns         = S( 8, 12);
-  const Score RookOnPawn          = S( 8, 24);
+  const int RankFactor[RANK_NB] = {0, 0, 0, 2, 6, 11, 16};
-  const Score TrappedRook         = S(92,  0);
-  const Score CloseEnemies        = S( 7,  0);
-  const Score SafeCheck           = S(20, 20);
-  const Score OtherCheck          = S(10, 10);
-  const Score ThreatByHangingPawn = S(71, 61);
-  const Score LooseEnemies        = S( 0, 25);
-  const Score WeakQueen           = S(35,  0);
-  const Score Hanging             = S(48, 27);
-  const Score ThreatByPawnPush    = S(38, 22);
-  const Score Unstoppable         = S( 0, 20);
-  const Score PawnlessFlank       = S(20, 80);
-  const Score HinderPassedPawn    = S( 7,  0);
-  // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
+  // KingProtector[PieceType-2] contains a bonus according to distance from king
+  const Score KingProtector[] = { S(-3, -5), S(-4, -3), S(-3, 0), S(-1, 1) };
-  // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
+  // Assorted bonuses and penalties used by evaluation
+  const Score MinorBehindPawn       = S( 16,  0);
+  const Score BishopPawns           = S(  8, 12);
+  const Score LongRangedBishop      = S( 22,  0);
+  const Score RookOnPawn            = S(  8, 24);
+  const Score TrappedRook           = S( 92,  0);
+  const Score WeakQueen             = S( 50, 10);
+  const Score CloseEnemies          = S(  7,  0);
+  const Score PawnlessFlank         = S( 20, 80);
+  const Score ThreatBySafePawn      = S(192,175);
+  const Score ThreatByRank          = S( 16,  3);
+  const Score Hanging               = S( 48, 27);
-  // happen in Chess960 games.
+  const Score WeakUnopposedPawn     = S(  5, 25);
+  const Score ThreatByPawnPush      = S( 38, 22);
+  const Score ThreatByAttackOnQueen = S( 38, 22);
+  const Score HinderPassedPawn      = S(  7,  0);
-  const Score TrappedBishopA1H1 = S(50, 50);
+  const Score TrappedBishopA1H1     = S( 50, 50);
   #undef S
   #undef V
   // KingAttackWeights[PieceType] contains king attack weights by piece type
   const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 };
   // Penalties for enemy's safe checks
-  const int QueenContactCheck = 997;
+  const int QueenSafeCheck  = 780;
-  const int QueenCheck        = 695;
-  const int RookCheck         = 638;
+  const int RookSafeCheck   = 880;
-  const int BishopCheck       = 538;
+  const int BishopSafeCheck = 435;
-  const int KnightCheck       = 874;
+  const int KnightSafeCheck = 790;
+  // Threshold for lazy and space evaluation
+  const Value LazyThreshold  = Value(1500);
+  const Value SpaceThreshold = Value(12222);
-  // eval_init() initializes king and attack bitboards for a given color
-  // adding pawn attacks. To be done at the beginning of the evaluation.
-  template<Color Us>
+  // initialize() computes king and pawn attacks, and the king ring bitboard
-  void eval_init(const Position& pos, EvalInfo& ei) {
+  // for a given color. This is done at the beginning of the evaluation.
-    const Color  Them = (Us == WHITE ? BLACK : WHITE);
+  template<Tracing T> template<Color Us>
-    const Square Down = (Us == WHITE ? SOUTH : NORTH);
+  void Evaluation<T>::initialize() {
-    ei.pinnedPieces[Us] = pos.pinned_pieces(Us);
+    const Color     Them = (Us == WHITE ? BLACK : WHITE);
-    Bitboard b = ei.attackedBy[Them][KING];
+    const Direction Up   = (Us == WHITE ? NORTH : SOUTH);
-    ei.attackedBy[Them][ALL_PIECES] |= b;
+    const Direction Down = (Us == WHITE ? SOUTH : NORTH);
-    ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
-    ei.attackedBy2[Us] = ei.attackedBy[Us][PAWN] & ei.attackedBy[Us][KING];
+    const Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB);
+    // Find our pawns on the first two ranks, and those which are blocked
+    Bitboard b = pos.pieces(Us, PAWN) & (shift<Down>(pos.pieces()) | LowRanks);
+    // Squares occupied by those pawns, by our king, or controlled by enemy pawns
+    // are excluded from the mobility area.
+    mobilityArea[Us] = ~(b | pos.square<KING>(Us) | pe->pawn_attacks(Them));
+    // Initialise the attack bitboards with the king and pawn information
+    b = attackedBy[Us][KING] = pos.attacks_from<KING>(pos.square<KING>(Us));
+    attackedBy[Us][PAWN] = pe->pawn_attacks(Us);
+    attackedBy2[Us]            = b & attackedBy[Us][PAWN];
+    attackedBy[Us][ALL_PIECES] = b | attackedBy[Us][PAWN];
-    // Init king safety tables only if we are going to use them
+    // Init our king safety tables only if we are going to use them
-    if (pos.non_pawn_material(Us) >= QueenValueMg)
+    if (pos.non_pawn_material(Them) >= RookValueMg + KnightValueMg)
+    {
-        ei.kingRing[Them] = b | shift<Down>(b);
+        kingRing[Us] = b;
+        if (relative_rank(Us, pos.square<KING>(Us)) == RANK_1)
-        b &= ei.attackedBy[Us][PAWN];
+            kingRing[Us] |= shift<Up>(b);
-        ei.kingAttackersCount[Us] = popcount(b);
+        kingAttackersCount[Them] = popcount(b & pe->pawn_attacks(Them));
-        ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
+        kingAdjacentZoneAttacksCount[Them] = kingAttackersWeight[Them] = 0;
+    }
     else
-        ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
+        kingRing[Us] = kingAttackersCount[Them] = 0;
+  }
   // evaluate_pieces() assigns bonuses and penalties to the pieces of a given
   // color and type.
-  template<bool DoTrace, Color Us = WHITE, PieceType Pt = KNIGHT>
+  template<Tracing T>  template<Color Us, PieceType Pt>
-  Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility,
+  Score Evaluation<T>::evaluate_pieces() {
-                        const Bitboard* mobilityArea) {
-    Bitboard b, bb;
-    Square s;
-    Score score = SCORE_ZERO;
-    const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1));
     const Color Them = (Us == WHITE ? BLACK : WHITE);
     const Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
                                                : Rank5BB | Rank4BB | Rank3BB);
     const Square* pl = pos.squares<Pt>(Us);
+    Bitboard b, bb;
+    Square s;
+    Score score = SCORE_ZERO;
-    ei.attackedBy[Us][Pt] = 0;
+    attackedBy[Us][Pt] = 0;
+    if (Pt == QUEEN)
+        attackedBy[Us][QUEEN_DIAGONAL] = 0;
     while ((s = *pl++) != SQ_NONE)
+    {
         // Find attacked squares, including x-ray attacks for bishops and rooks
-        b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN))
+        b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
-          : Pt ==   ROOK ? attacks_bb<  ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
+          : Pt ==   ROOK ? attacks_bb<  ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
                          : pos.attacks_from<Pt>(s);
-        if (ei.pinnedPieces[Us] & s)
+        if (pos.pinned_pieces(Us) & s)
             b &= LineBB[pos.square<KING>(Us)][s];
-        ei.attackedBy2[Us] |= ei.attackedBy[Us][ALL_PIECES] & b;
+        attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b;
-        ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b;
+        attackedBy[Us][ALL_PIECES] |= attackedBy[Us][Pt] |= b;
+        if (Pt == QUEEN)
+            attackedBy[Us][QUEEN_DIAGONAL] |= b & PseudoAttacks[BISHOP][s];
-        if (b & ei.kingRing[Them])
+        if (b & kingRing[Them])
+        {
-            ei.kingAttackersCount[Us]++;
+            kingAttackersCount[Us]++;
-            ei.kingAttackersWeight[Us] += KingAttackWeights[Pt];
+            kingAttackersWeight[Us] += KingAttackWeights[Pt];
-            ei.kingAdjacentZoneAttacksCount[Us] += popcount(b & ei.attackedBy[Them][KING]);
+            kingAdjacentZoneAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
+        }
-        if (Pt == QUEEN)
-            b &= ~(  ei.attackedBy[Them][KNIGHT]
-                   | ei.attackedBy[Them][BISHOP]
-                   | ei.attackedBy[Them][ROOK]);
+        int mob = popcount(b & mobilityArea[Us]);
-        int mob = popcount(b & mobilityArea[Us]);
+        mobility[Us] += MobilityBonus[Pt - 2][mob];
-        mobility[Us] += MobilityBonus[Pt][mob];
+        // Bonus for this piece as a king protector
+        score += KingProtector[Pt - 2] * distance(s, pos.square<KING>(Us));
         if (Pt == BISHOP || Pt == KNIGHT)
+        {
             // Bonus for outpost squares
-            bb = OutpostRanks & ~ei.pi->pawn_attacks_span(Them);
+            bb = OutpostRanks & ~pe->pawn_attacks_span(Them);
             if (bb & s)
-                score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)];
+                score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & s)] * 2;
             else
+            {
                 bb &= b & ~pos.pieces(Us);
                 if (bb)
-                   score += ReachableOutpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)];
+                   score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & bb)];
+            }
             // Bonus when behind a pawn
             if (    relative_rank(Us, s) < RANK_5
                 && (pos.pieces(PAWN) & (s + pawn_push(Us))))
                 score += MinorBehindPawn;
-            // Penalty for pawns on the same color square as the bishop
             if (Pt == BISHOP)
+            {
+                // Penalty for pawns on the same color square as the bishop
-                score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
+                score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s);
+                // Bonus for bishop on a long diagonal which can "see" both center squares
+                if (more_than_one(Center & (attacks_bb<BISHOP>(s, pos.pieces(PAWN)) | s)))
+                    score += LongRangedBishop;
+            }
             // An important Chess960 pattern: A cornered bishop blocked by a friendly
             // pawn diagonally in front of it is a very serious problem, especially
             // when that pawn is also blocked.
             if (   Pt == BISHOP
                 && pos.is_chess960()
                 && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+            {
-                Square d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
+                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))                ? TrappedBishopA1H1 * 4
                             : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
                                                                               : TrappedBishopA1H1;
+            }
             // Bonus for aligning with enemy pawns on the same rank/file
             if (relative_rank(Us, s) >= RANK_5)
                 score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]);
             // Bonus when on an open or semi-open file
-            if (ei.pi->semiopen_file(Us, file_of(s)))
+            if (pe->semiopen_file(Us, file_of(s)))
-                score += RookOnFile[!!ei.pi->semiopen_file(Them, file_of(s))];
+                score += RookOnFile[bool(pe->semiopen_file(Them, file_of(s)))];
-            // Penalize when trapped by the king, even more if the king cannot castle
+            // Penalty when trapped by the king, even more if the king cannot castle
             else if (mob <= 3)
+            {
                 Square ksq = pos.square<KING>(Us);
                 if (   ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
-                    && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
-                    && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
+                    && !pe->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
                     score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
+            }
+        }
         if (Pt == QUEEN)
             if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, pinners))
                 score -= WeakQueen;
+        }
+    }
-    if (DoTrace)
+    if (T)
         Trace::add(Pt, Us, score);
-    // Recursively call evaluate_pieces() of next piece type until KING is excluded
-    return score - evaluate_pieces<DoTrace, Them, NextPt>(pos, ei, mobility, mobilityArea);
+    return score;
+  }
-  template<>
-  Score evaluate_pieces<false, WHITE, KING>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; }
-  template<>
-  Score evaluate_pieces< true, WHITE, KING>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; }
   // evaluate_king() assigns bonuses and penalties to a king of a given color
-  const Bitboard WhiteCamp = Rank1BB | Rank2BB | Rank3BB | Rank4BB | Rank5BB;
-  const Bitboard BlackCamp = Rank8BB | Rank7BB | Rank6BB | Rank5BB | Rank4BB;
-  const Bitboard QueenSide   = FileABB | FileBBB | FileCBB | FileDBB;
+  template<Tracing T>  template<Color Us>
-  const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
+  Score Evaluation<T>::evaluate_king() {
-  const Bitboard KingSide    = FileEBB | FileFBB | FileGBB | FileHBB;
-  const Bitboard KingFlank[COLOR_NB][FILE_NB] = {
-    { QueenSide   & WhiteCamp, QueenSide & WhiteCamp, QueenSide & WhiteCamp, CenterFiles & WhiteCamp,
-      CenterFiles & WhiteCamp, KingSide  & WhiteCamp, KingSide  & WhiteCamp, KingSide    & WhiteCamp },
-    { QueenSide   & BlackCamp, QueenSide & BlackCamp, QueenSide & BlackCamp, CenterFiles & BlackCamp,
-      CenterFiles & BlackCamp, KingSide  & BlackCamp, KingSide  & BlackCamp, KingSide    & BlackCamp },
-  };
-  template<Color Us, bool DoTrace>
-  Score evaluate_king(const Position& pos, const EvalInfo& ei) {
-    const Color Them = (Us == WHITE ? BLACK : WHITE);
+    const Color     Them = (Us == WHITE ? BLACK : WHITE);
-    const Square  Up = (Us == WHITE ? NORTH : SOUTH);
+    const Bitboard  Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
+                                        : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
-    Bitboard undefended, b, b1, b2, safe, other;
-    int kingDanger;
     const Square ksq = pos.square<KING>(Us);
+    Bitboard weak, b, b1, b2, safe, unsafeChecks;
     // King shelter and enemy pawns storm
-    Score score = ei.pi->king_safety<Us>(pos, ksq);
+    Score score = pe->king_safety<Us>(pos, ksq);
     // Main king safety evaluation
-    if (ei.kingAttackersCount[Them])
+    if (kingAttackersCount[Them] > (1 - pos.count<QUEEN>(Them)))
+    {
-        // Find the attacked squares which are defended only by the king...
+        // Attacked squares defended at most once by our queen or king
-        undefended =   ei.attackedBy[Them][ALL_PIECES]
+        weak =  attackedBy[Them][ALL_PIECES]
-                    &  ei.attackedBy[Us][KING]
-                    & ~ei.attackedBy2[Us];
+              & ~attackedBy2[Us]
-        // ... and those which are not defended at all in the larger king ring
-        b =  ei.attackedBy[Them][ALL_PIECES] & ~ei.attackedBy[Us][ALL_PIECES]
+              & (attackedBy[Us][KING] | attackedBy[Us][QUEEN] | ~attackedBy[Us][ALL_PIECES]);
-           & ei.kingRing[Us] & ~pos.pieces(Them);
-        // Initialize the 'kingDanger' variable, which will be transformed
-        // later into a king danger score. The initial value is based on the
-        // number and types of the enemy's attacking pieces, the number of
-        // attacked and undefended squares around our king and the quality of
+        unsafeChecks = 0; // Pierre-Marie Baty -- fixed variable initialization
-        // the pawn shelter (current 'score' value).
-        kingDanger =  std::min(807, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
-                    + 101 * ei.kingAdjacentZoneAttacksCount[Them]
-                    + 235 * popcount(undefended)
-                    + 134 * (popcount(b) + !!ei.pinnedPieces[Us])
-                    - 717 * !pos.count<QUEEN>(Them)
-                    -   7 * mg_value(score) / 5 - 5;
+        int kingDanger = 0;
-        // Analyse the enemy's safe queen contact checks. Firstly, find the
-        // undefended squares around the king reachable by the enemy queen...
-        b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
-        // ...and keep squares supported by another enemy piece
-        kingDanger += QueenContactCheck * popcount(b & ei.attackedBy2[Them]);
-        // Analyse the safe enemy's checks which are possible on next move...
-        safe  = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them));
-        // ... and some other potential checks, only requiring the square to be
+        // Analyse the safe enemy's checks which are possible on next move
-        // safe from pawn-attacks, and not being occupied by a blocked pawn.
-        other = ~(   ei.attackedBy[Us][PAWN]
+        safe  = ~pos.pieces(Them);
-                  | (pos.pieces(Them, PAWN) & shift<Up>(pos.pieces(PAWN))));
+        safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);
-        b1 = pos.attacks_from<ROOK  >(ksq);
+        b1 = attacks_bb<ROOK  >(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
-        b2 = pos.attacks_from<BISHOP>(ksq);
+        b2 = attacks_bb<BISHOP>(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
         // Enemy queen safe checks
-        if ((b1 | b2) & ei.attackedBy[Them][QUEEN] & safe)
+        if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN])
-            kingDanger += QueenCheck, score -= SafeCheck;
+            kingDanger += QueenSafeCheck;
-        // For other pieces, also consider the square safe if attacked twice,
-        // and only defended by a queen.
-        safe |=  ei.attackedBy2[Them]
+        b1 &= attackedBy[Them][ROOK];
-               & ~(ei.attackedBy2[Us] | pos.pieces(Them))
-               & ei.attackedBy[Us][QUEEN];
+        b2 &= attackedBy[Them][BISHOP];
-        // Enemy rooks safe and other checks
+        // Enemy rooks checks
-        if (b1 & ei.attackedBy[Them][ROOK] & safe)
+        if (b1 & safe)
-            kingDanger += RookCheck, score -= SafeCheck;
+            kingDanger += RookSafeCheck;
+        else
+            unsafeChecks |= b1;
+        // Enemy bishops checks
+        if (b2 & safe)
-        else if (b1 & ei.attackedBy[Them][ROOK] & other)
+            kingDanger += BishopSafeCheck;
+        else
-            score -= OtherCheck;
+            unsafeChecks |= b2;
-        // Enemy bishops safe and other checks
-        if (b2 & ei.attackedBy[Them][BISHOP] & safe)
-            kingDanger += BishopCheck, score -= SafeCheck;
-        else if (b2 & ei.attackedBy[Them][BISHOP] & other)
-            score -= OtherCheck;
-        // Enemy knights safe and other checks
+        // Enemy knights checks
-        b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT];
+        b = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
         if (b & safe)
-            kingDanger += KnightCheck, score -= SafeCheck;
+            kingDanger += KnightSafeCheck;
+        else
+            unsafeChecks |= b;
+        // Unsafe or occupied checking squares will also be considered, as long as
-        else if (b & other)
+        // the square is in the attacker's mobility area.
-            score -= OtherCheck;
+        unsafeChecks &= mobilityArea[Them];
+        kingDanger +=        kingAttackersCount[Them] * kingAttackersWeight[Them]
+                     + 102 * kingAdjacentZoneAttacksCount[Them]
+                     + 191 * popcount(kingRing[Us] & weak)
+                     + 143 * popcount(pos.pinned_pieces(Us) | unsafeChecks)
+                     - 848 * !pos.count<QUEEN>(Them)
+                     -   9 * mg_value(score) / 8
+                     +  40;
-        // Compute the king danger score and subtract it from the evaluation
+        // Transform the kingDanger units into a Score, and subtract it from the evaluation
         if (kingDanger > 0)
+        {
+            int mobilityDanger = mg_value(mobility[Them] - mobility[Us]);
+            kingDanger = std::max(0, kingDanger + mobilityDanger);
-            score -= make_score(std::min(kingDanger * kingDanger / 4096,  2 * int(BishopValueMg)), 0);
+            score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
+        }
+    }
     // King tropism: firstly, find squares that opponent attacks in our king flank
     File kf = file_of(ksq);
-    b = ei.attackedBy[Them][ALL_PIECES] & KingFlank[Us][kf];
+    b = attackedBy[Them][ALL_PIECES] & KingFlank[kf] & Camp;
     assert(((Us == WHITE ? b << 4 : b >> 4) & b) == 0);
     assert(popcount(Us == WHITE ? b << 4 : b >> 4) == popcount(b));
     // Secondly, add the squares which are attacked twice in that flank and
     // which are not defended by our pawns.
     b =  (Us == WHITE ? b << 4 : b >> 4)
-       | (b & ei.attackedBy2[Them] & ~ei.attackedBy[Us][PAWN]);
+       | (b & attackedBy2[Them] & ~attackedBy[Us][PAWN]);
     score -= CloseEnemies * popcount(b);
     // Penalty when our king is on a pawnless flank
-    if (!(pos.pieces(PAWN) & (KingFlank[WHITE][kf] | KingFlank[BLACK][kf])))
+    if (!(pos.pieces(PAWN) & KingFlank[kf]))
         score -= PawnlessFlank;
-    if (DoTrace)
+    if (T)
         Trace::add(KING, Us, score);
     return score;
+  }
   // evaluate_threats() assigns bonuses according to the types of the attacking
   // and the attacked pieces.
-  template<Color Us, bool DoTrace>
+  template<Tracing T>  template<Color Us>
-  Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
+  Score Evaluation<T>::evaluate_threats() {
-    const Color Them        = (Us == WHITE ? BLACK      : WHITE);
+    const Color     Them     = (Us == WHITE ? BLACK      : WHITE);
-    const Square Up         = (Us == WHITE ? NORTH      : SOUTH);
+    const Direction Up       = (Us == WHITE ? NORTH      : SOUTH);
-    const Square Left       = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
+    const Direction Left     = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
-    const Square Right      = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
+    const Direction Right    = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
-    const Bitboard TRank2BB = (Us == WHITE ? Rank2BB    : Rank7BB);
-    const Bitboard TRank7BB = (Us == WHITE ? Rank7BB    : Rank2BB);
+    const Bitboard  TRank3BB = (Us == WHITE ? Rank3BB    : Rank6BB);
-    enum { Minor, Rook };
-    Bitboard b, weak, defended, safeThreats;
+    Bitboard b, weak, defended, stronglyProtected, safeThreats;
     Score score = SCORE_ZERO;
-    // Small bonus if the opponent has loose pawns or pieces
-    if (   (pos.pieces(Them) ^ pos.pieces(Them, QUEEN, KING))
-        & ~(ei.attackedBy[Us][ALL_PIECES] | ei.attackedBy[Them][ALL_PIECES]))
-        score += LooseEnemies;
     // Non-pawn enemies attacked by a pawn
-    weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Us][PAWN];
+    weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & attackedBy[Us][PAWN];
     if (weak)
+    {
-        b = pos.pieces(Us, PAWN) & ( ~ei.attackedBy[Them][ALL_PIECES]
+        b = pos.pieces(Us, PAWN) & ( ~attackedBy[Them][ALL_PIECES]
-                                    | ei.attackedBy[Us][ALL_PIECES]);
+                                    | attackedBy[Us][ALL_PIECES]);
         safeThreats = (shift<Right>(b) | shift<Left>(b)) & weak;
-        if (weak ^ safeThreats)
-            score += ThreatByHangingPawn;
-        while (safeThreats)
-            score += ThreatBySafePawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))];
+        score += ThreatBySafePawn * popcount(safeThreats);
+    }
+    // Squares strongly protected by the opponent, either because they attack the
+    // square with a pawn, or because they attack the square twice and we don't.
+    stronglyProtected =  attackedBy[Them][PAWN]
+                       | (attackedBy2[Them] & ~attackedBy2[Us]);
-    // Non-pawn enemies defended by a pawn
+    // Non-pawn enemies, strongly protected
-    defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Them][PAWN];
+    defended =  (pos.pieces(Them) ^ pos.pieces(Them, PAWN))
+              & stronglyProtected;
-    // Enemies not defended by a pawn and under our attack
+    // Enemies not strongly protected and under our attack
     weak =   pos.pieces(Them)
-          & ~ei.attackedBy[Them][PAWN]
+          & ~stronglyProtected
-          &  ei.attackedBy[Us][ALL_PIECES];
+          &  attackedBy[Us][ALL_PIECES];
     // Add a bonus according to the kind of attacking pieces
     if (defended | weak)
+    {
-        b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+        b = (defended | weak) & (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP]);
         while (b)
+        {
+            Square s = pop_lsb(&b);
-            score += Threat[Minor][type_of(pos.piece_on(pop_lsb(&b)))];
+            score += ThreatByMinor[type_of(pos.piece_on(s))];
+            if (type_of(pos.piece_on(s)) != PAWN)
+                score += ThreatByRank * (int)relative_rank(Them, s);
+        }
-        b = (pos.pieces(Them, QUEEN) | weak) & ei.attackedBy[Us][ROOK];
+        b = (pos.pieces(Them, QUEEN) | weak) & attackedBy[Us][ROOK];
         while (b)
+        {
+            Square s = pop_lsb(&b);
-            score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))];
+            score += ThreatByRook[type_of(pos.piece_on(s))];
+            if (type_of(pos.piece_on(s)) != PAWN)
+                score += ThreatByRank * (int)relative_rank(Them, s);
+        }
-        score += Hanging * popcount(weak & ~ei.attackedBy[Them][ALL_PIECES]);
+        score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]);
-        b = weak & ei.attackedBy[Us][KING];
+        b = weak & attackedBy[Us][KING];
         if (b)
             score += ThreatByKing[more_than_one(b)];
+    }
-    // Bonus if some pawns can safely push and attack an enemy piece
+    // Bonus for opponent unopposed weak pawns
-    b = pos.pieces(Us, PAWN) & ~TRank7BB;
+    if (pos.pieces(Us, ROOK, QUEEN))
-    b = shift<Up>(b | (shift<Up>(b & TRank2BB) & ~pos.pieces()));
+        score += WeakUnopposedPawn * pe->weak_unopposed(Them);
-    b &=  ~pos.pieces()
+    // Find squares where our pawns can push on the next move
-        & ~ei.attackedBy[Them][PAWN]
+    b  = shift<Up>(pos.pieces(Us, PAWN)) & ~pos.pieces();
-        & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
+    b |= shift<Up>(b & TRank3BB) & ~pos.pieces();
+    // Keep only the squares which are not completely unsafe
+    b &= ~attackedBy[Them][PAWN]
+        & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]);
+    // Add a bonus for each new pawn threats from those squares
     b =  (shift<Left>(b) | shift<Right>(b))
        &  pos.pieces(Them)
-       & ~ei.attackedBy[Us][PAWN];
+       & ~attackedBy[Us][PAWN];
     score += ThreatByPawnPush * popcount(b);
+    // Add a bonus for safe slider attack threats on opponent queen
+    safeThreats = ~pos.pieces(Us) & ~attackedBy2[Them] & attackedBy2[Us];
+    b =  (attackedBy[Us][BISHOP] & attackedBy[Them][QUEEN_DIAGONAL])
+       | (attackedBy[Us][ROOK  ] & attackedBy[Them][QUEEN] & ~attackedBy[Them][QUEEN_DIAGONAL]);
+    score += ThreatByAttackOnQueen * popcount(b & safeThreats);
-    if (DoTrace)
+    if (T)
         Trace::add(THREAT, Us, score);
     return score;
+  }
+  // helper used by evaluate_passed_pawns to cap the distance
+  template<Tracing T>
+  int Evaluation<T>::king_distance(Color c, Square s) {
+    return std::min(distance(pos.square<KING>(c), s), 5);
+  }
-  // evaluate_passed_pawns() evaluates the passed pawns of the given color
+  // evaluate_passed_pawns() evaluates the passed pawns and candidate passed
+  // pawns of the given color.
-  template<Color Us, bool DoTrace>
+  template<Tracing T>  template<Color Us>
-  Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei) {
+  Score Evaluation<T>::evaluate_passed_pawns() {
-    const Color Them = (Us == WHITE ? BLACK : WHITE);
+    const Color     Them = (Us == WHITE ? BLACK : WHITE);
+    const Direction Up   = (Us == WHITE ? NORTH : SOUTH);
     Bitboard b, bb, squaresToQueen, defendedSquares, unsafeSquares;
     Score score = SCORE_ZERO;
-    b = ei.pi->passed_pawns(Us);
+    b = pe->passed_pawns(Us);
     while (b)
+    {
         Square s = pop_lsb(&b);
-        assert(pos.pawn_passed(Us, s));
-        assert(!(pos.pieces(PAWN) & forward_bb(Us, s)));
+        assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));
-        bb = forward_bb(Us, s) & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
+        bb = forward_file_bb(Us, s) & (attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
         score -= HinderPassedPawn * popcount(bb);
-        int r = relative_rank(Us, s) - RANK_2;
+        int r = relative_rank(Us, s);
-        int rr = r * (r - 1);
+        int rr = RankFactor[r];
         Value mbonus = Passed[MG][r], ebonus = Passed[EG][r];
         if (rr)
+        {
-            Square blockSq = s + pawn_push(Us);
+            Square blockSq = s + Up;
             // Adjust bonus based on the king's proximity
-            ebonus +=  distance(pos.square<KING>(Them), blockSq) * 5 * rr
+            ebonus += (king_distance(Them, blockSq) * 5 - king_distance(Us, blockSq) * 2) * rr;
-                     - distance(pos.square<KING>(Us  ), blockSq) * 2 * rr;
             // If blockSq is not the queening square then consider also a second push
-            if (relative_rank(Us, blockSq) != RANK_8)
+            if (r != RANK_7)
-                ebonus -= distance(pos.square<KING>(Us), blockSq + pawn_push(Us)) * rr;
+                ebonus -= king_distance(Us, blockSq + Up) * rr;
             // If the pawn is free to advance, then increase the bonus
             if (pos.empty(blockSq))
+            {
                 // If there is a rook or queen attacking/defending the pawn from behind,
                 // consider all the squaresToQueen. Otherwise consider only the squares
                 // in the pawn's path attacked or occupied by the enemy.
-                defendedSquares = unsafeSquares = squaresToQueen = forward_bb(Us, s);
+                defendedSquares = unsafeSquares = squaresToQueen = forward_file_bb(Us, s);
-                bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
+                bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
                 if (!(pos.pieces(Us) & bb))
-                    defendedSquares &= ei.attackedBy[Us][ALL_PIECES];
+                    defendedSquares &= attackedBy[Us][ALL_PIECES];
                 if (!(pos.pieces(Them) & bb))
-                    unsafeSquares &= ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them);
+                    unsafeSquares &= attackedBy[Them][ALL_PIECES] | pos.pieces(Them);
                 // If there aren't any enemy attacks, assign a big bonus. Otherwise
                 // assign a smaller bonus if the block square isn't attacked.
                 int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0;
                 mbonus += k * rr, ebonus += k * rr;
+            }
             else if (pos.pieces(Us) & blockSq)
                 mbonus += rr + r * 2, ebonus += rr + r * 2;
         } // rr != 0
+        // Scale down bonus for candidate passers which need more than one
+        // pawn push to become passed or have a pawn in front of them.
+        if (!pos.pawn_passed(Us, s + Up) || (pos.pieces(PAWN) & forward_file_bb(Us, s)))
+            mbonus /= 2, ebonus /= 2;
         score += make_score(mbonus, ebonus) + PassedFile[file_of(s)];
+    }
-    if (DoTrace)
+    if (T)
         Trace::add(PASSED, Us, score);
-    // Add the scores to the middlegame and endgame eval
     return score;
+  }
   // evaluate_space() computes the space evaluation for a given side. The
   // space evaluation is a simple bonus based on the number of safe squares
   // available for minor pieces on the central four files on ranks 2--4. Safe
   // squares one, two or three squares behind a friendly pawn are counted
   // twice. Finally, the space bonus is multiplied by a weight. The aim is to
   // improve play on game opening.
-  template<Color Us>
+  template<Tracing T>  template<Color Us>
-  Score evaluate_space(const Position& pos, const EvalInfo& ei) {
+  Score Evaluation<T>::evaluate_space() {
     const Color Them = (Us == WHITE ? BLACK : WHITE);
     const Bitboard SpaceMask =
-      Us == WHITE ? (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB)
+      Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB)
-                  : (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB);
+                  : CenterFiles & (Rank7BB | Rank6BB | Rank5BB);
     // Find the safe squares for our pieces inside the area defined by
     // SpaceMask. A square is unsafe if it is attacked by an enemy
     // pawn, or if it is undefended and attacked by an enemy piece.
     Bitboard safe =   SpaceMask
                    & ~pos.pieces(Us, PAWN)
-                   & ~ei.attackedBy[Them][PAWN]
+                   & ~attackedBy[Them][PAWN]
-                   & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
+                   & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]);
     // Find all squares which are at most three squares behind some friendly pawn
     Bitboard behind = pos.pieces(Us, PAWN);
     behind |= (Us == WHITE ? behind >>  8 : behind <<  8);
     behind |= (Us == WHITE ? behind >> 16 : behind << 16);
     // Since SpaceMask[Us] is fully on our half of the board...
     assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
-    // ...count safe + (behind & safe) with a single popcount
+    // ...count safe + (behind & safe) with a single popcount.
     int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
-    bonus = std::min(16, bonus);
-    int weight = pos.count<ALL_PIECES>(Us) - 2 * ei.pi->open_files();
+    int weight = pos.count<ALL_PIECES>(Us) - 2 * pe->open_files();
-    return make_score(bonus * weight * weight / 18, 0);
+    return make_score(bonus * weight * weight / 16, 0);
+  }
   // evaluate_initiative() computes the initiative correction value for the
   // position, i.e., second order bonus/malus based on the known attacking/defending
   // status of the players.
+  template<Tracing T>
-  Score evaluate_initiative(const Position& pos, int asymmetry, Value eg) {
+  Score Evaluation<T>::evaluate_initiative(Value eg) {
     int kingDistance =  distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
                       - distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
-    int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
+    bool bothFlanks = (pos.pieces(PAWN) & QueenSide) && (pos.pieces(PAWN) & KingSide);
     // Compute the initiative bonus for the attacking side
-    int initiative = 8 * (asymmetry + kingDistance - 15) + 12 * pawns;
+    int initiative = 8 * (pe->pawn_asymmetry() + kingDistance - 17) + 12 * pos.count<PAWN>() + 16 * bothFlanks;
     // Now apply the bonus: note that we find the attacking side by extracting
     // the sign of the endgame value, and that we carefully cap the bonus so
-    // that the endgame score will never be divided by more than two.
+    // that the endgame score will never change sign after the bonus.
-    int value = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg / 2));
+    int v = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg));
+    if (T)
+        Trace::add(INITIATIVE, make_score(0, v));
-    return make_score(0, value);
+    return make_score(0, v);
+  }
   // evaluate_scale_factor() computes the scale factor for the winning side
+  template<Tracing T>
-  ScaleFactor evaluate_scale_factor(const Position& pos, const EvalInfo& ei, Value eg) {
+  ScaleFactor Evaluation<T>::evaluate_scale_factor(Value eg) {
     Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
-    ScaleFactor sf = ei.me->scale_factor(pos, strongSide);
+    ScaleFactor sf = me->scale_factor(pos, strongSide);
     // If we don't already have an unusual scale factor, check for certain
     // types of endgames, and use a lower scale for those.
-    if (    ei.me->game_phase() < PHASE_MIDGAME
-        && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
+    if (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN)
+    {
         if (pos.opposite_bishops())
+        {
             // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
             // is almost a draw, in case of KBP vs KB, it is even more a draw.
             if (   pos.non_pawn_material(WHITE) == BishopValueMg
                 && pos.non_pawn_material(BLACK) == BishopValueMg)
-                sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9);
+                return more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9);
             // Endgame with opposite-colored bishops, but also other pieces. Still
             // a bit drawish, but not as drawish as with only the two bishops.
-            else
-                sf = ScaleFactor(46);
+            return ScaleFactor(46);
+        }
         // Endings where weaker side can place his king in front of the opponent's
         // pawns are drawish.
         else if (    abs(eg) <= BishopValueEg
                  &&  pos.count<PAWN>(strongSide) <= 2
                  && !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
-            sf = ScaleFactor(37 + 7 * pos.count<PAWN>(strongSide));
+            return ScaleFactor(37 + 7 * pos.count<PAWN>(strongSide));
+    }
     return sf;
+  }
-} // namespace
+  // value() is the main function of the class. It computes the various parts of
+  // the evaluation and returns the value of the position from the point of view
+  // of the side to move.
-/// evaluate() is the main evaluation function. It returns a static evaluation
+  template<Tracing T>
-/// of the position from the point of view of the side to move.
+  Value Evaluation<T>::value() {
-template<bool DoTrace>
+    assert(!pos.checkers());
-Value Eval::evaluate(const Position& pos) {
+    // Probe the material hash table
-  assert(!pos.checkers());
+    me = Material::probe(pos);
+    // If we have a specialized evaluation function for the current material
-  Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO };
+    // configuration, call it and return.
+    if (me->specialized_eval_exists())
-  EvalInfo ei;
+        return me->evaluate(pos);
+    // Initialize score by reading the incrementally updated scores included in
-  // Probe the material hash table
+    // the position object (material + piece square tables) and the material
+    // imbalance. Score is computed internally from the white point of view.
-  ei.me = Material::probe(pos);
+    Score score = pos.psq_score() + me->imbalance() + Eval::Contempt;
-  // If we have a specialized evaluation function for the current material
-  // configuration, call it and return.
+    // Probe the pawn hash table
-  if (ei.me->specialized_eval_exists())
+    pe = Pawns::probe(pos);
-      return ei.me->evaluate(pos);
+    score += pe->pawns_score();
-  // Initialize score by reading the incrementally updated scores included in
+    // Early exit if score is high
-  // the position object (material + piece square tables) and the material
+    Value v = (mg_value(score) + eg_value(score)) / 2;
-  // imbalance. Score is computed internally from the white point of view.
+    if (abs(v) > LazyThreshold)
-  Score score = pos.psq_score() + ei.me->imbalance();
+       return pos.side_to_move() == WHITE ? v : -v;
-  // Probe the pawn hash table
+    // Main evaluation begins here
-  ei.pi = Pawns::probe(pos);
-  score += ei.pi->pawns_score();
-  // Initialize attack and king safety bitboards
-  ei.attackedBy[WHITE][ALL_PIECES] = ei.attackedBy[BLACK][ALL_PIECES] = 0;
-  ei.attackedBy[WHITE][KING] = pos.attacks_from<KING>(pos.square<KING>(WHITE));
-  ei.attackedBy[BLACK][KING] = pos.attacks_from<KING>(pos.square<KING>(BLACK));
-  eval_init<WHITE>(pos, ei);
+    initialize<WHITE>();
-  eval_init<BLACK>(pos, ei);
+    initialize<BLACK>();
-  // Pawns blocked or on ranks 2 and 3 will be excluded from the mobility area
+    score += evaluate_pieces<WHITE, KNIGHT>() - evaluate_pieces<BLACK, KNIGHT>();
-  Bitboard blockedPawns[] = {
+    score += evaluate_pieces<WHITE, BISHOP>() - evaluate_pieces<BLACK, BISHOP>();
-    pos.pieces(WHITE, PAWN) & (shift<SOUTH>(pos.pieces()) | Rank2BB | Rank3BB),
+    score += evaluate_pieces<WHITE, ROOK  >() - evaluate_pieces<BLACK, ROOK  >();
-    pos.pieces(BLACK, PAWN) & (shift<NORTH>(pos.pieces()) | Rank7BB | Rank6BB)
+    score += evaluate_pieces<WHITE, QUEEN >() - evaluate_pieces<BLACK, QUEEN >();
-  };
-  // Do not include in mobility area squares protected by enemy pawns, or occupied
-  // by our blocked pawns or king.
-  Bitboard mobilityArea[] = {
+    score += mobility[WHITE] - mobility[BLACK];
-    ~(ei.attackedBy[BLACK][PAWN] | blockedPawns[WHITE] | pos.square<KING>(WHITE)),
-    ~(ei.attackedBy[WHITE][PAWN] | blockedPawns[BLACK] | pos.square<KING>(BLACK))
-  };
-  // Evaluate all pieces but king and pawns
+    score +=  evaluate_king<WHITE>()
-  score += evaluate_pieces<DoTrace>(pos, ei, mobility, mobilityArea);
-  score += mobility[WHITE] - mobility[BLACK];
+            - evaluate_king<BLACK>();
-  // Evaluate kings after all other pieces because we need full attack
-  // information when computing the king safety evaluation.
-  score +=  evaluate_king<WHITE, DoTrace>(pos, ei)
+    score +=  evaluate_threats<WHITE>()
-          - evaluate_king<BLACK, DoTrace>(pos, ei);
+            - evaluate_threats<BLACK>();
-  // Evaluate tactical threats, we need full attack information including king
-  score +=  evaluate_threats<WHITE, DoTrace>(pos, ei)
+    score +=  evaluate_passed_pawns<WHITE>()
-          - evaluate_threats<BLACK, DoTrace>(pos, ei);
+            - evaluate_passed_pawns<BLACK>();
-  // Evaluate passed pawns, we need full attack information including king
+    if (pos.non_pawn_material() >= SpaceThreshold)
-  score +=  evaluate_passed_pawns<WHITE, DoTrace>(pos, ei)
+        score +=  evaluate_space<WHITE>()
-          - evaluate_passed_pawns<BLACK, DoTrace>(pos, ei);
+                - evaluate_space<BLACK>();
-  // If both sides have only pawns, score for potential unstoppable pawns
-  if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK))
-  {
-      Bitboard b;
-      if ((b = ei.pi->passed_pawns(WHITE)) != 0)
+    score += evaluate_initiative(eg_value(score));
-          score += Unstoppable * int(relative_rank(WHITE, frontmost_sq(WHITE, b)));
+    // Interpolate between a middlegame and a (scaled by 'sf') endgame score
+    ScaleFactor sf = evaluate_scale_factor(eg_value(score));
-      if ((b = ei.pi->passed_pawns(BLACK)) != 0)
+    v =  mg_value(score) * int(me->game_phase())
-          score -= Unstoppable * int(relative_rank(BLACK, frontmost_sq(BLACK, b)));
+       + eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
-  }
-  // Evaluate space for both sides, only during opening
-  if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 12222)
-      score +=  evaluate_space<WHITE>(pos, ei)
+    v /= int(PHASE_MIDGAME);
-              - evaluate_space<BLACK>(pos, ei);
-  // Evaluate position potential for the winning side
+    // In case of tracing add all remaining individual evaluation terms
+    if (T)
+    {
+        Trace::add(MATERIAL, pos.psq_score());
+        Trace::add(IMBALANCE, me->imbalance());
-  score += evaluate_initiative(pos, ei.pi->pawn_asymmetry(), eg_value(score));
+        Trace::add(PAWN, pe->pawns_score());
+        Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
+        if (pos.non_pawn_material() >= SpaceThreshold)
+            Trace::add(SPACE, evaluate_space<WHITE>()
+                            , evaluate_space<BLACK>());
+        Trace::add(TOTAL, score);
+    }
-  // Evaluate scale factor for the winning side
-  ScaleFactor sf = evaluate_scale_factor(pos, ei, eg_value(score));
+    return pos.side_to_move() == WHITE ? v : -v; // Side to move point of view
+  }
-  // Interpolate between a middlegame and a (scaled by 'sf') endgame score
-  Value v =  mg_value(score) * int(ei.me->game_phase())
+} // namespace
-           + eg_value(score) * int(PHASE_MIDGAME - ei.me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
-  v /= int(PHASE_MIDGAME);
+Score Eval::Contempt = SCORE_ZERO;
-  // In case of tracing add all remaining individual evaluation terms
+/// evaluate() is the evaluator for the outer world. It returns a static evaluation
-  if (DoTrace)
-  {
-      Trace::add(MATERIAL, pos.psq_score());
-      Trace::add(IMBALANCE, ei.me->imbalance());
-      Trace::add(PAWN, ei.pi->pawns_score());
-      Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
-      Trace::add(SPACE, evaluate_space<WHITE>(pos, ei)
-                      , evaluate_space<BLACK>(pos, ei));
+/// of the position from the point of view of the side to move.
-      Trace::add(TOTAL, score);
-  }
+Value Eval::evaluate(const Position& pos)
+{
-  return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view
+   return Evaluation<>(pos).value() + Eval::Tempo;
+}
-// Explicit template instantiations
-template Value Eval::evaluate<true >(const Position&);
-template Value Eval::evaluate<false>(const Position&);
 /// trace() is like evaluate(), but instead of returning a value, it returns
 /// a string (suitable for outputting to stdout) that contains the detailed
 /// descriptions and values of each evaluation term. Useful for debugging.
 std::string Eval::trace(const Position& pos) {
   std::memset(scores, 0, sizeof(scores));
-  Value v = evaluate<true>(pos);
+  Value v = Evaluation<TRACE>(pos).value() + Eval::Tempo;
   v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
   std::stringstream ss;
   ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
      << "      Eval term |    White    |    Black    |    Total    \n"
      << "----------------+-------------+-------------+-------------\n"
      << "       Material | " << Term(MATERIAL)
      << "      Imbalance | " << Term(IMBALANCE)
      << "          Pawns | " << Term(PAWN)
      << "        Knights | " << Term(KNIGHT)
-     << "         Bishop | " << Term(BISHOP)
+     << "        Bishops | " << Term(BISHOP)
      << "          Rooks | " << Term(ROOK)
      << "         Queens | " << Term(QUEEN)
      << "       Mobility | " << Term(MOBILITY)
      << "    King safety | " << Term(KING)
      << "        Threats | " << Term(THREAT)
      << "   Passed pawns | " << Term(PASSED)
      << "          Space | " << Term(SPACE)
+     << "     Initiative | " << Term(INITIATIVE)
      << "----------------+-------------+-------------+-------------\n"
      << "          Total | " << Term(TOTAL);
   ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";

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Games.Chess Giants//engine-stockfish/evaluate.cpp – Rev 154 → 169