/*
  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
  Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
  Copyright (C) 2015-2020 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.

  Stockfish is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <algorithm>
#include <cassert>
#include <cstring>   // For std::memset
#include <iomanip>
#include <sstream>

#include "bitboard.h"
#include "evaluate.h"
#include "material.h"
#include "pawns.h"
#include "thread.h"

namespace Trace {

  enum Tracing { NO_TRACE, TRACE };

  enum Term { // The first 8 entries are reserved for PieceType
    MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, WINNABLE, VARIANT, TOTAL, TERM_NB
  };

  Score scores[TERM_NB][COLOR_NB];

  double to_cp(Value v) { return double(v) / PawnValueEg; }

  void add(int idx, Color c, Score s) {
    scores[idx][c] = s;
  }

  void add(int idx, Score w, Score b = SCORE_ZERO) {
    scores[idx][WHITE] = w;
    scores[idx][BLACK] = b;
  }

  std::ostream& operator<<(std::ostream& os, Score s) {
    os << std::setw(5) << to_cp(mg_value(s)) << " "
       << std::setw(5) << to_cp(eg_value(s));
    return os;
  }

  std::ostream& operator<<(std::ostream& os, Term t) {

    if (t == MATERIAL || t == IMBALANCE || t == WINNABLE || t == TOTAL)
        os << " ----  ----"    << " | " << " ----  ----";
    else
        os << scores[t][WHITE] << " | " << scores[t][BLACK];

    os << " | " << scores[t][WHITE] - scores[t][BLACK] << "\n";
    return os;
  }
}

using namespace Trace;

namespace {

  // Threshold for lazy and space evaluation
  constexpr Value LazyThreshold1  = Value(1400);
  constexpr Value LazyThreshold2  = Value(1300);
  constexpr Value SpaceThreshold[VARIANT_NB] = {
    Value(12222),
#ifdef ANTI
    Value(12222),
#endif
#ifdef ATOMIC
    Value(12222),
#endif
#ifdef CRAZYHOUSE
    Value(12222),
#endif
#ifdef EXTINCTION
    Value(12222),
#endif
#ifdef GRID
    2 * MidgameLimit,
#endif
#ifdef HORDE
    Value(12222),
#endif
#ifdef KOTH
    VALUE_ZERO,
#endif
#ifdef LOSERS
    Value(12222),
#endif
#ifdef RACE
    Value(12222),
#endif
#ifdef THREECHECK
    Value(12222),
#endif
#ifdef TWOKINGS
    Value(12222),
#endif
  };

  // KingAttackWeights[PieceType] contains king attack weights by piece type
  constexpr int KingAttackWeights[VARIANT_NB][PIECE_TYPE_NB] = {
    { 0, 0, 81, 52, 44, 10 },
#ifdef ANTI
    {},
#endif
#ifdef ATOMIC
    { 0, 0, 76, 64, 46, 11 },
#endif
#ifdef CRAZYHOUSE
    { 0, 0, 112, 87, 63, 2 },
#endif
#ifdef EXTINCTION
    {},
#endif
#ifdef GRID
    { 0, 0, 89, 62, 47, 11 },
#endif
#ifdef HORDE
    { 0, 0, 77, 55, 44, 10 },
#endif
#ifdef KOTH
    { 0, 0, 76, 48, 44, 10 },
#endif
#ifdef LOSERS
    { 0, 0, 77, 55, 44, 10 },
#endif
#ifdef RACE
    {},
#endif
#ifdef THREECHECK
    { 0, 0, 115, 64, 62, 35 },
#endif
#ifdef TWOKINGS
    { 0, 0, 77, 55, 44, 10 },
#endif
  };

  // Per-variant king danger malus factors
  constexpr int KingDangerParams[VARIANT_NB][11] = {
    {   185,  148,   98,   69,    3, -873, -100,   -6,   -4,   37,    0 },
#ifdef ANTI
    {},
#endif
#ifdef ATOMIC
    {   166,  146,   98,  274,    3, -654, -100,  -12,   -4,   37,   29 },
#endif
#ifdef CRAZYHOUSE
    {   463,  129,   99,  121,    3, -631,  -99,   -6,   -4,   37,  315 },
#endif
#ifdef EXTINCTION
    {},
#endif
#ifdef GRID
    {   211,  158,   98,  119,    3, -722, -100,   -9,   -4,   37,    0 },
#endif
#ifdef HORDE
    {   235,  134,   98,  101,    3, -717, -100,  -11,   -4,   37,    0 },
#endif
#ifdef KOTH
    {   229,  131,   98,   85,    3, -658, -100,   -9,   -4,   37,    0 },
#endif
#ifdef LOSERS
    {   235,  134,   98,  101,    3, -717, -100, -357,   -4,   37,    0 },
#endif
#ifdef RACE
    {     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0 },
#endif
#ifdef THREECHECK
    {   136,  106,   98,   85,    3, -613, -100,   -7,   -4,   37,  181 },
#endif
#ifdef TWOKINGS
    {   155,  136,   98,   92,    3, -967, -100,   -8,   -4,   37,    0 },
#endif
  };

  // SafeCheck[PieceType][single/multiple] contains safe check bonus by piece type,
  // higher if multiple safe checks are possible for that piece type.
  constexpr int SafeCheck[][2] = {
      {}, {435, 683}, {792, 1283}, {645, 967}, {1084, 1897}, {772, 1119}
  };
#ifdef THREECHECK
  // In Q8 fixed point
  constexpr int ThreeCheckKSFactors[CHECKS_NB] = { 573, 581, 856, 0 };
#endif

#define S(mg, eg) make_score(mg, eg)

  // MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game,
  // indexed by piece type and number of attacked squares in the mobility area.
  constexpr Score MobilityBonus[VARIANT_NB][4][32] = {
    {
    { S(-62,-81), S(-53,-56), S(-12,-31), S( -4,-16), S(  3,  5), S( 13, 11), // Knight
      S( 22, 17), S( 28, 20), S( 33, 25) },
    { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishop
      S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86),
      S( 91, 88), S( 98, 97) },
    { S(-60,-78), S(-20,-17), S(  2, 23), S(  3, 39), S(  3, 70), S( 11, 99), // Rook
      S( 22,103), S( 31,121), S( 40,134), S( 40,139), S( 41,158), S( 48,164),
      S( 57,168), S( 57,169), S( 62,172) },
    { S(-30,-48), S(-12,-30), S( -8, -7), S( -9, 19), S( 20, 40), S( 23, 55), // Queen
      S( 23, 59), S( 35, 75), S( 38, 78), S( 53, 96), S( 64, 96), S( 65,100),
      S( 65,121), S( 66,127), S( 67,131), S( 67,133), S( 72,136), S( 72,141),
      S( 77,147), S( 79,150), S( 93,151), S(108,168), S(108,168), S(108,171),
      S(110,182), S(114,182), S(114,192), S(116,219) }
    },
#ifdef ANTI
    {
      { S(-150,-152), S(-112,-108), S(-18,-52), S( -4,-20), S( 12, 10), S( 30, 22), // Knights
        S(  44,  52), S(  60,  56), S( 72, 58) },
      { S(-96,-116), S(-42,-38), S( 32, -4), S( 52, 24), S( 74, 44), S(102, 84), // Bishops
        S(108, 108), S(126,116), S(130,126), S(142,140), S(158,148), S(162,172),
        S(184, 180), S(194,188) },
      { S(-112,-156), S(-50,-36), S(-22, 52), S(-10,110), S( -8,140), S( -2,162), // Rooks
        S(  16, 218), S( 28,240), S( 42,256), S( 46,286), S( 62,308), S( 64,320),
        S(  86, 330), S( 98,336), S(118,338) },
      { S(-80,-70), S(-50,-24), S(  4, 14), S(  8, 38), S( 28, 74), S( 48,110), // Queens
        S( 50,124), S( 80,152), S( 86,158), S( 94,174), S(108,188), S(112,204),
        S(120,222), S(140,232), S(144,236), S(146,244), S(150,256), S(154,260),
        S(170,266), S(188,272), S(198,280), S(216,314), S(224,316), S(226,322),
        S(236,348), S(238,354), S(246,382), S(256,398) }
    },
#endif
#ifdef ATOMIC
    {
      { S(-86,-77), S(-79,-64), S(-36,-40), S( -2,-24), S( 14,  8), S( 23, 25), // Knights
        S( 40, 26), S( 30, 23), S( 37, 29) },
      { S(-55,-65), S(-17,-34), S( 13, -9), S( 24, 20), S( 22, 25), S( 57, 39), // Bishops
        S( 32, 52), S( 66, 66), S( 51, 52), S( 56, 74), S( 73, 76), S( 85, 81),
        S( 93, 90), S(108, 87) },
      { S(-61,-73), S(-32,-28), S(-18,  9), S(-19, 30), S(-19, 57), S( 20, 78), // Rooks
        S( 12,104), S( 11,134), S( 21,133), S( 33,166), S( 35,168), S( 38,185),
        S( 25,172), S( 60,182), S( 58,155) },
      { S(-43,-43), S(-14,-16), S( -5,  1), S(  0, 23), S(  6, 24), S( 23, 59), // Queens
        S( 20, 55), S( 32, 66), S( 47, 89), S( 29, 77), S( 47, 89), S( 69,103),
        S( 63,110), S( 76,131), S( 73,115), S( 48,132), S( 58,131), S( 75,135),
        S( 82,122), S(111,130), S(114,144), S(101,139), S(106,146), S(107,167),
        S(115,157), S(129,175), S(132,176), S(130,210) }
    },
#endif
#ifdef CRAZYHOUSE
    {
      { S(-126, -96), S(-103,-31), S(-90,-27), S(-40,  3), S(  0,  3), S(  4,  0), // Knights
        S(  20,  12), S(  15, 33), S( 50, 46) },
      { S(-156, -79), S(-115,-43), S( 42,-14), S( 35, 26), S( 64, 26), S( 74, 38), // Bishops
        S(  70,  46), S(  83, 71), S( 70, 68), S( 66, 80), S( 64, 68), S( 70, 77),
        S(  97,  92), S(  89, 98) },
      { S( -53, -53), S( -22, -8), S(-48, 30), S(-14, 57), S( -4, 77), S( 11, 87), // Rooks
        S(   7, 115), S(  12,123), S( 27,120), S(  6,140), S( 55,156), S( 18,161),
        S(  51, 161), S(  54,171), S( 52,166) },
      { S( -26, -56), S( -24,-14), S(  7, 14), S(  8, 15), S( 18, 34), S( 14, 41), // Queens
        S(  28,  58), S(  33, 66), S( 40, 70), S( 47, 74), S( 50,100), S( 52,106),
        S(  59, 111), S(  50, 95), S( 60,115), S( 61,126), S( 75,144), S( 82,119),
        S(  95, 137), S( 102,138), S(100,142), S(119,154), S(129,156), S(107,156),
        S( 111, 177), S( 115,181), S(124,197), S(124,199) }
    },
#endif
#ifdef EXTINCTION
    {
      { S(-123, -90), S( -91,-32), S(-61,-29), S(-38,  3), S(  0,  3), S(  4,  0), // Knights
        S(  19,  12), S(  15, 33), S( 52, 45) },
      { S(-153, -80), S(-112,-41), S( 41,-14), S( 35, 24), S( 62, 26), S( 75, 41), // Bishops
        S(  72,  48), S(  85, 74), S( 74, 65), S( 66, 79), S( 64, 69), S( 73, 80),
        S( 107,  92), S(  96,101) },
      { S( -59, -51), S( -20, -8), S(-54, 32), S(-15, 54), S( -4, 70), S( 11, 84), // Rooks
        S(   6, 113), S(  13,123), S( 27,114), S(  6,144), S( 60,162), S( 19,162),
        S(  48, 170), S(  57,170), S( 52,177) },
      { S( -27, -56), S( -24,-14), S(  7, 13), S(  9, 16), S( 18, 37), S( 14, 40), // Queens
        S(  29,  56), S(  34, 64), S( 39, 73), S( 49, 65), S( 50, 98), S( 50,106),
        S(  60, 107), S(  53, 92), S( 62,119), S( 69,130), S( 77,145), S( 84,120),
        S(  90, 153), S(  98,131), S(106,139), S(116,147), S(127,157), S(112,154),
        S( 121, 174), S( 124,167), S(126,194), S(130,190) }
    },
#endif
#ifdef GRID
    {
      { S(-75,-76), S(-57,-54), S( -9,-28), S( -2,-10), S(  6,  5), S( 14, 12), // Knights
        S( 22, 26), S( 29, 29), S( 36, 29) },
      { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishops
        S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86),
        S( 91, 88), S( 98, 97) },
      { S(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rooks
        S(  9,112), S( 16,118), S( 30,132), S( 29,142), S( 32,155), S( 38,165),
        S( 46,166), S( 48,169), S( 58,171) },
      { S(-39,-36), S(-21,-15), S(  3,  8), S(  3, 18), S( 14, 34), S( 22, 54), // Queens
        S( 28, 61), S( 41, 73), S( 43, 79), S( 48, 92), S( 56, 94), S( 60,104),
        S( 60,113), S( 66,120), S( 67,123), S( 70,126), S( 71,133), S( 73,136),
        S( 79,140), S( 88,143), S( 88,148), S( 99,166), S(102,170), S(102,175),
        S(106,184), S(109,191), S(113,206), S(116,212) }
    },
#endif
#ifdef HORDE
    {
      { S(-126,-90), S( -7,-22), S( -46,-25), S( 19,7), S( -53, 71), S( 31, -1), // Knights
        S(  -6, 51), S(-12, 47), S( -9, -56) },
      { S( -46,-2), S(30,66), S( 18, -27), S( 86, 21), S( 65, 11), S(147, 45), // Bishops
        S(  98, 38), S( 95, 52), S(122, 45), S( 95, 33), S( 89,103), S( 85, -9),
        S( 105, 70), S(131, 82) },
      { S( -56,-78), S(-25,-18), S(-11, 26), S( -5, 55), S( -4, 70), S( -1, 81), // Rooks
        S(   8,109), S( 14,120), S( 21,128), S( 23,143), S( 31,154), S( 32,160),
        S(  43,165), S( 49,168), S( 59,169) },
      { S( -40,-35), S(-25,-12), S(  2,  7), S(  4, 19), S( 14, 37), S( 24, 55), // Queens
        S(  25, 62), S( 40, 76), S( 43, 79), S( 47, 87), S( 54, 94), S( 56,102),
        S(  60,111), S( 70,116), S( 72,118), S( 73,122), S( 75,128), S( 77,130),
        S(  85,133), S( 94,136), S( 99,140), S(108,157), S(112,158), S(113,161),
        S( 118,174), S(119,177), S(123,191), S(128,199) }
    },
#endif
#ifdef KOTH
    {
      { S(-75,-76), S(-56,-54), S( -9,-26), S( -2,-10), S(  6,  5), S( 15, 11), // Knights
        S( 22, 26), S( 30, 28), S( 36, 29) },
      { S(-48,-58), S(-21,-19), S( 16, -2), S( 26, 12), S( 37, 22), S( 51, 42), // Bishops
        S( 54, 54), S( 63, 58), S( 65, 63), S( 71, 70), S( 79, 74), S( 81, 86),
        S( 92, 90), S( 97, 94) },
      { S(-56,-78), S(-25,-18), S(-11, 26), S( -5, 55), S( -4, 70), S( -1, 81), // Rooks
        S(  8,109), S( 14,120), S( 21,128), S( 23,143), S( 31,154), S( 32,160),
        S( 43,165), S( 49,168), S( 59,169) },
      { S(-40,-35), S(-25,-12), S(  2,  7), S(  4, 19), S( 14, 37), S( 24, 55), // Queens
        S( 25, 62), S( 40, 76), S( 43, 79), S( 47, 87), S( 54, 94), S( 56,102),
        S( 60,111), S( 70,116), S( 72,118), S( 73,122), S( 75,128), S( 77,130),
        S( 85,133), S( 94,136), S( 99,140), S(108,157), S(112,158), S(113,161),
        S(118,174), S(119,177), S(123,191), S(128,199) }
    },
#endif
#ifdef LOSERS
    {
      { S(-150,-152), S(-112,-108), S(-18,-52), S( -4,-20), S( 12, 10), S( 30, 22), // Knights
        S(  44,  52), S(  60,  56), S( 72, 58) },
      { S(-96,-116), S(-42,-38), S( 32, -4), S( 52, 24), S( 74, 44), S(102, 84), // Bishops
        S(108, 108), S(126,116), S(130,126), S(142,140), S(158,148), S(162,172),
        S(184, 180), S(194,188) },
      { S(-112,-156), S(-50,-36), S(-22, 52), S(-10,110), S( -8,140), S( -2,162), // Rooks
        S(  16, 218), S( 28,240), S( 42,256), S( 46,286), S( 62,308), S( 64,320),
        S(  86, 330), S( 98,336), S(118,338) },
      { S(-80,-70), S(-50,-24), S(  4, 14), S(  8, 38), S( 28, 74), S( 48,110), // Queens
        S( 50,124), S( 80,152), S( 86,158), S( 94,174), S(108,188), S(112,204),
        S(120,222), S(140,232), S(144,236), S(146,244), S(150,256), S(154,260),
        S(170,266), S(188,272), S(198,280), S(216,314), S(224,316), S(226,322),
        S(236,348), S(238,354), S(246,382), S(256,398) }
    },
#endif
#ifdef RACE
    {
      { S(-132,-117), S( -89,-110), S(-13,-49), S(-11,-15), S(-10,-30), S( 29, 17), // Knights
        S(  13,  32), S(  79,  69), S(109, 79) },
      { S(-101,-119), S( -19, -27), S( 27, -9), S( 35, 30), S( 62, 31), S(115, 72), // Bishops
        S(  91,  99), S( 138, 122), S(129,119), S(158,156), S(153,162), S(143,189),
        S( 172, 181), S( 196, 204) },
      { S(-131,-162), S( -57, -37), S( -8, 47), S( 12, 93), S(  3,127), S( 10,139), // Rooks
        S(   3, 240), S(  18, 236), S( 44,251), S( 44,291), S( 49,301), S( 67,316),
        S( 100, 324), S(  97, 340), S(110,324) },
      { S( -87, -68), S( -73,  -2), S( -7,  9), S( -5, 16), S( 39, 76), S( 39,118), // Queens
        S(  64, 131), S(  86, 169), S( 86,175), S( 78,166), S( 97,195), S(123,216),
        S( 137, 200), S( 155, 247), S(159,260), S(136,252), S(156,279), S(160,251),
        S( 165, 251), S( 194, 267), S(204,271), S(216,331), S(226,304), S(223,295),
        S( 239, 316), S( 228, 365), S(240,385), S(249,377) }
    },
#endif
#ifdef THREECHECK
    {
      { S(-74,-76), S(-55,-54), S( -9,-26), S( -2,-10), S(  6,  5), S( 15, 11), // Knights
        S( 22, 26), S( 31, 27), S( 37, 29) },
      { S(-49,-56), S(-23,-18), S( 15, -2), S( 25, 12), S( 36, 22), S( 50, 42), // Bishops
        S( 53, 54), S( 64, 57), S( 67, 63), S( 71, 68), S( 84, 76), S( 79, 87),
        S( 95, 91), S( 98, 93) },
      { S(-57,-76), S(-25,-18), S(-11, 25), S( -5, 53), S( -4, 70), S( -1, 78), // Rooks
        S(  8,111), S( 14,116), S( 22,125), S( 24,148), S( 31,159), S( 31,173),
        S( 44,163), S( 50,162), S( 56,168) },
      { S(-42,-35), S(-25,-12), S(  2,  7), S(  4, 19), S( 14, 37), S( 24, 53), // Queens
        S( 26, 63), S( 39, 80), S( 42, 77), S( 48, 88), S( 53, 96), S( 57, 96),
        S( 61,108), S( 71,116), S( 70,116), S( 74,125), S( 75,133), S( 78,133),
        S( 85,137), S( 97,135), S(103,141), S(107,165), S(109,153), S(115,162),
        S(119,164), S(121,184), S(121,192), S(131,203) }
    },
#endif
#ifdef TWOKINGS
    {
      { S(-75,-76), S(-57,-54), S( -9,-28), S( -2,-10), S(  6,  5), S( 14, 12), // Knights
        S( 22, 26), S( 29, 29), S( 36, 29) },
      { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishops
        S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86),
        S( 91, 88), S( 98, 97) },
      { S(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rooks
        S(  9,112), S( 16,118), S( 30,132), S( 29,142), S( 32,155), S( 38,165),
        S( 46,166), S( 48,169), S( 58,171) },
      { S(-39,-36), S(-21,-15), S(  3,  8), S(  3, 18), S( 14, 34), S( 22, 54), // Queens
        S( 28, 61), S( 41, 73), S( 43, 79), S( 48, 92), S( 56, 94), S( 60,104),
        S( 60,113), S( 66,120), S( 67,123), S( 70,126), S( 71,133), S( 73,136),
        S( 79,140), S( 88,143), S( 88,148), S( 99,166), S(102,170), S(102,175),
        S(106,184), S(109,191), S(113,206), S(116,212) }
    },
#endif
  };

  // KingProtector[knight/bishop] contains penalty for each distance unit to own king
  constexpr Score KingProtector[] = { S(8, 9), S(6, 9) };

  // Outpost[knight/bishop] contains bonuses for each knight or bishop occupying a
  // pawn protected square on rank 4 to 6 which is also safe from a pawn attack.
  constexpr Score Outpost[] = { S(56, 36), S(30, 23) };

  // PassedRank[Rank] contains a bonus according to the rank of a passed pawn
  constexpr Score PassedRank[VARIANT_NB][RANK_NB] = {
    {
    S(0, 0), S(10, 28), S(17, 33), S(15, 41), S(62, 72), S(168, 177), S(276, 260)
    },
#ifdef ANTI
    { S(0, 0), S(5, 7), S(5, 14), S(31, 38), S(73, 73), S(166, 166), S(252, 252) },
#endif
#ifdef ATOMIC
    { S(0, 0), S(95, 86), S(118, 43), S(94, 61), S(142, 62), S(196, 150), S(204, 256) },
#endif
#ifdef CRAZYHOUSE
    { S(0, 0), S(15, 27), S(23, 13), S(13, 19), S(88, 111), S(177, 140), S(229, 293) },
#endif
#ifdef EXTINCTION
    { S(0, 0), S(5, 7), S(5, 14), S(31, 38), S(73, 73), S(166, 166), S(252, 252) },
#endif
#ifdef GRID
    { S(0, 0), S(11, 2), S(4, 0), S(27, 34), S(58, 17), S(168, 165), S(251, 253) },
#endif
#ifdef HORDE
    { S(0, 0), S(-66, 10), S(-25, 7), S(66, -12), S(68, 81), S(72, 210), S(250, 258) },
#endif
#ifdef KOTH
    { S(0, 0), S(5, 7), S(5, 14), S(31, 38), S(73, 73), S(166, 166), S(252, 252) },
#endif
#ifdef LOSERS
    { S(0, 0), S(5, 8), S(5, 13), S(31, 36), S(72, 72), S(170, 159), S(276, 251) },
#endif
#ifdef RACE
    {},
#endif
#ifdef THREECHECK
    { S(0, 0), S(5, 7), S(5, 14), S(31, 38), S(73, 73), S(166, 166), S(252, 252) },
#endif
#ifdef TWOKINGS
    { S(0, 0), S(5, 7), S(5, 14), S(31, 38), S(73, 73), S(166, 166), S(252, 252) },
#endif
  };

  // RookOnFile[semiopen/open] contains bonuses for each rook when there is
  // no (friendly) pawn on the rook file.
  constexpr Score RookOnFile[] = { S(19, 7), S(48, 29) };

  // ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to
  // which piece type attacks which one. Attacks on lesser pieces which are
  // pawn-defended are not considered.
  constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
    S(0, 0), S(5, 32), S(57, 41), S(77, 56), S(88, 119), S(79, 161)
  };

  constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
    S(0, 0), S(3, 46), S(37, 68), S(42, 60), S(0, 38), S(58, 41)
  };

  // Assorted bonuses and penalties
#ifdef ATOMIC
  constexpr Score AtomicConfinedKing = S(100, 100);
  constexpr Score ThreatByBlast = S(80, 80);
#endif
#ifdef HORDE
  constexpr Score HordeShelter = S(71, 61);
#endif
#ifdef THREECHECK
  constexpr Score ChecksGivenBonus[CHECKS_NB] = {
      S(0, 0),
      S(444, 181),
      S(2425, 603),
      S(0, 0)
  };
#endif
#ifdef KOTH
  constexpr Score KothDistanceBonus[6] = {
    S(1949, 1934), S(454, 364), S(151, 158), S(75, 85), S(42, 49), S(0, 0)
  };
  constexpr Score KothSafeCenter = S(163, 207);
#endif
#ifdef ANTI
  constexpr Score PieceCountAnti    = S(119, 123);
  constexpr Score ThreatsAnti[]     = { S(192, 203), S(411, 322) };
  constexpr Score AttacksAnti[2][2][PIECE_TYPE_NB] = {
    {
      { S( 30, 141), S( 26,  94), S(161, 105), S( 70, 123), S( 61,  72), S( 78, 12), S(139, 115) },
      { S( 56,  89), S( 82, 107), S(114,  93), S(110, 115), S(188, 112), S( 73, 59), S(122,  59) }
    },
    {
      { S(119, 142), S( 99, 105), S(123, 193), S(142,  37), S(118,  96), S( 50, 12), S( 91,  85) },
      { S( 58,  81), S( 66, 110), S(105, 153), S(100, 143), S(140, 113), S(145, 73), S(153, 154) }
    }
  };
#endif
#ifdef LOSERS
  constexpr Score ThreatsLosers[]     = { S(216, 279), S(441, 341) };
  constexpr Score AttacksLosers[2][2][PIECE_TYPE_NB] = {
    {
      { S( 27, 140), S( 23,  95), S(160, 112), S( 78, 129), S( 65,  75), S( 70, 13), S(146, 123) },
      { S( 58,  82), S( 80, 112), S(124,  87), S(103, 110), S(185, 107), S( 72, 60), S(126,  62) }
    },
    {
      { S(111, 127), S(102,  95), S(121, 183), S(140,  37), S(120,  99), S( 55, 11), S( 88,  93) },
      { S( 56,  69), S( 72, 124), S(109, 154), S( 98, 149), S(129, 113), S(147, 72), S(157, 152) }
    }
  };
#endif
#ifdef CRAZYHOUSE
  constexpr int KingDangerInHand[PIECE_TYPE_NB] = {
    79, 16, 200, 61, 138, 152
  };
  constexpr Score DropMobilityBonus = S(30, 30);
#endif
#ifdef RACE
  // Bonus for distance of king from 8th rank
  constexpr Score KingRaceBonus[RANK_NB] = {
    S(14282, 14493), S(6369, 5378), S(4224, 3557), S(2633, 2219),
    S( 1614,  1456), S( 975,  885), S( 528,  502), S(   0,    0)
  };
#endif
  constexpr Score BadOutpost          = S( -7, 36);
  constexpr Score BishopOnKingRing    = S( 24,  0);
  constexpr Score BishopPawns         = S(  3,  7);
  constexpr Score BishopXRayPawns     = S(  4,  5);
  constexpr Score CorneredBishop      = S( 50, 50);
  constexpr Score FlankAttacks[VARIANT_NB] = {
    S(  8,  0),
#ifdef ANTI
    S( 0,  0),
#endif
#ifdef ATOMIC
    S(17,  0),
#endif
#ifdef CRAZYHOUSE
    S(14, 20),
#endif
#ifdef EXTINCTION
    S( 0,  0),
#endif
#ifdef GRID
    S( 7,  0),
#endif
#ifdef HORDE
    S( 7,  0),
#endif
#ifdef KOTH
    S( 7,  0),
#endif
#ifdef LOSERS
    S( 7,  0),
#endif
#ifdef RACE
    S( 0,  0),
#endif
#ifdef THREECHECK
    S(16,  9),
#endif
#ifdef TWOKINGS
    S( 7,  0),
#endif
  };
  constexpr Score Hanging             = S( 69, 36);
  constexpr Score KnightOnQueen       = S( 16, 11);
  constexpr Score LongDiagonalBishop  = S( 45,  0);
  constexpr Score MinorBehindPawn     = S( 18,  3);
  constexpr Score PassedFile          = S( 11,  8);
  constexpr Score PawnlessFlank       = S( 17, 95);
  constexpr Score QueenInfiltration   = S( -2, 14);
  constexpr Score ReachableOutpost    = S( 31, 22);
  constexpr Score RestrictedPiece     = S(  7,  7);
  constexpr Score RookOnKingRing      = S( 16,  0);
  constexpr Score RookOnQueenFile     = S(  6, 11);
  constexpr Score SliderOnQueen       = S( 60, 18);
  constexpr Score ThreatByKing        = S( 24, 89);
  constexpr Score ThreatByPawnPush    = S( 48, 39);
  constexpr Score ThreatBySafePawn    = S(173, 94);
  constexpr Score TrappedRook         = S( 55, 13);
  constexpr Score WeakQueenProtection = S( 14,  0);
  constexpr Score WeakQueen           = S( 56, 15);


#undef S

  // Evaluation class computes and stores attacks tables and other working data
  template<Tracing T>
  class Evaluation {

  public:
    Evaluation() = delete;
    explicit Evaluation(const Position& p) : pos(p) {}
    Evaluation& operator=(const Evaluation&) = delete;
    Value value();

  private:
    template<Color Us> void initialize();
    template<Color Us, PieceType Pt> Score pieces();
    template<Color Us> Score king() const;
    template<Color Us> Score threats() const;
    template<Color Us> Score passed() const;
    template<Color Us> Score space() const;
    template<Color Us> Score variant() const;
    Value winnable(Score score) const;

    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. Special "piece types" which
    // is also calculated is ALL_PIECES.
    Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];

    // attackedBy2[color] are the squares attacked by at least 2 units of a given
    // color, including x-rays. But diagonal x-rays through pawns are not computed.
    Bitboard attackedBy2[COLOR_NB];

    // kingRing[color] are the squares adjacent to the king plus some other
    // very near squares, depending on king position.
    Bitboard kingRing[COLOR_NB];

    // kingAttackersCount[color] is the number of pieces of the given color
    // which attack a square in the kingRing of the enemy king.
    int kingAttackersCount[COLOR_NB];

    // kingAttackersWeight[color] is the sum of the "weights" of the pieces of
    // the given color which attack a square in the kingRing of the enemy king.
    // The weights of the individual piece types are given by the elements in
    // the KingAttackWeights array.
    int kingAttackersWeight[COLOR_NB];

    // kingAttacksCount[color] is the number of attacks by the given 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 kingAttacksCount[WHITE].
    int kingAttacksCount[COLOR_NB];
  };


  // Evaluation::initialize() computes king and pawn attacks, and the king ring
  // bitboard for a given color. This is done at the beginning of the evaluation.

  template<Tracing T> template<Color Us>
  void Evaluation<T>::initialize() {

    constexpr Color     Them = ~Us;
    constexpr Direction Up   = pawn_push(Us);
    constexpr Direction Down = -Up;
    constexpr Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB : Rank7BB | Rank6BB);

#ifdef HORDE
    const Square ksq = (pos.is_horde() && pos.is_horde_color(Us)) ? SQ_NONE : pos.square<KING>(Us);
#else
    const Square ksq = pos.square<KING>(Us);
#endif

    Bitboard dblAttackByPawn = pawn_double_attacks_bb<Us>(pos.pieces(Us, PAWN));

    // Find our pawns that are blocked or on the first two ranks
    Bitboard b = pos.pieces(Us, PAWN) & (shift<Down>(pos.pieces()) | LowRanks);

    // Squares occupied by those pawns, by our king or queen, by blockers to attacks on our king
    // or controlled by enemy pawns are excluded from the mobility area.
#ifdef ANTI
    if (pos.is_anti())
        mobilityArea[Us] = ~b;
    else
#endif
#ifdef HORDE
    if (pos.is_horde() && pos.is_horde_color(Us))
        mobilityArea[Us] = ~(b | pe->pawn_attacks(Them));
    else
#endif
    mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pos.blockers_for_king(Us) | pe->pawn_attacks(Them));

    // Initialize attackedBy[] for king and pawns
#ifdef ANTI
    if (pos.is_anti())
    {
        attackedBy[Us][KING] = 0;
        Bitboard kings = pos.pieces(Us, KING);
        while (kings)
            attackedBy[Us][KING] |= attacks_bb<KING>(pop_lsb(&kings));
    }
    else
#endif
#ifdef EXTINCTION
    if (pos.is_extinction())
    {
        attackedBy[Us][KING] = 0;
        Bitboard kings = pos.pieces(Us, KING);
        while (kings)
            attackedBy[Us][KING] |= attacks_bb<KING>(pop_lsb(&kings));
    }
    else
#endif
#ifdef HORDE
    if (pos.is_horde() && pos.is_horde_color(Us))
        attackedBy[Us][KING] = 0;
    else
#endif
#ifdef PLACEMENT
    if (pos.is_placement() && pos.count_in_hand<KING>(Us))
        attackedBy[Us][KING] = 0;
    else
#endif
    attackedBy[Us][KING] = attacks_bb<KING>(ksq);
    attackedBy[Us][PAWN] = pe->pawn_attacks(Us);
    attackedBy[Us][ALL_PIECES] = attackedBy[Us][KING] | attackedBy[Us][PAWN];
    attackedBy2[Us] = dblAttackByPawn | (attackedBy[Us][KING] & attackedBy[Us][PAWN]);

    // Init our king safety tables
#ifdef ANTI
    if (pos.is_anti()) {} else
#endif
#ifdef EXTINCTION
    if (pos.is_extinction()) {} else
#endif
#ifdef HORDE
    if (pos.is_horde() && pos.is_horde_color(Us)) {} else
#endif
#ifdef PLACEMENT
    if (pos.is_placement() && pos.count_in_hand<KING>(Us)) {} else
#endif
    {
    Square s = make_square(Utility::clamp(file_of(ksq), FILE_B, FILE_G),
                           Utility::clamp(rank_of(ksq), RANK_2, RANK_7));
    kingRing[Us] = attacks_bb<KING>(s) | s;
    }

    kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them));
    kingAttacksCount[Them] = kingAttackersWeight[Them] = 0;

    // Remove from kingRing[] the squares defended by two pawns
    kingRing[Us] &= ~dblAttackByPawn;
  }


  // Evaluation::pieces() scores pieces of a given color and type

  template<Tracing T> template<Color Us, PieceType Pt>
  Score Evaluation<T>::pieces() {

    constexpr Color     Them = ~Us;
    constexpr Direction Down = -pawn_push(Us);
    constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
                                                   : Rank5BB | Rank4BB | Rank3BB);
    const Square* pl = pos.squares<Pt>(Us);

    Bitboard b, bb;
    Score score = SCORE_ZERO;

    attackedBy[Us][Pt] = 0;

    for (Square s = *pl; s != SQ_NONE; s = *++pl)
    {
        // Find attacked squares, including x-ray attacks for bishops and rooks
        b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
          : Pt ==   ROOK ? attacks_bb<  ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
                         : attacks_bb<Pt>(s, pos.pieces());

#ifdef GRID
        if (pos.is_grid())
            b &= ~pos.grid_bb(s);
#endif
        if (pos.blockers_for_king(Us) & s)
            b &= line_bb(pos.square<KING>(Us), s);

        attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b;
        attackedBy[Us][Pt] |= b;
        attackedBy[Us][ALL_PIECES] |= b;

        if (b & kingRing[Them])
        {
            kingAttackersCount[Us]++;
            kingAttackersWeight[Us] += KingAttackWeights[pos.variant()][Pt];
            kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
        }

        else if (Pt == ROOK && (file_bb(s) & kingRing[Them]))
            score += RookOnKingRing;

        else if (Pt == BISHOP && (attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & kingRing[Them]))
            score += BishopOnKingRing;

        int mob = popcount(b & mobilityArea[Us]);

        mobility[Us] += MobilityBonus[pos.variant()][Pt - 2][mob];
#ifdef ANTI
        if (pos.is_anti())
            continue;
#endif
#ifdef HORDE
        if (pos.is_horde() && pos.is_horde_color(Us))
            continue;
#endif
#ifdef PLACEMENT
        if (pos.is_placement() && pos.count_in_hand<KING>(Us))
            continue;
#endif
#ifdef LOSERS
        if (pos.is_losers())
            continue;
#endif

        if (Pt == BISHOP || Pt == KNIGHT)
        {
            // Bonus if the piece is on an outpost square or can reach one
            // Reduced bonus for knights (BadOutpost) if few relevant targets
            bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
            Bitboard targets = pos.pieces(Them) & ~pos.pieces(PAWN);

            if (   Pt == KNIGHT
                && bb & s & ~CenterFiles // on a side outpost
                && !(b & targets)        // no relevant attacks
                && (!more_than_one(targets & (s & QueenSide ? QueenSide : KingSide))))
                score += BadOutpost;
            else if (bb & s)
                score += Outpost[Pt == BISHOP];
            else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
                score += ReachableOutpost;

            // Bonus for a knight or bishop shielded by pawn
            if (shift<Down>(pos.pieces(PAWN)) & s)
                score += MinorBehindPawn;

            // Penalty if the piece is far from the king
            score -= KingProtector[Pt == BISHOP] * distance(pos.square<KING>(Us), s);

            if (Pt == BISHOP)
            {
                // Penalty according to the number of our pawns on the same color square as the
                // bishop, bigger when the center files are blocked with pawns and smaller
                // when the bishop is outside the pawn chain.
                Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());

                score -= BishopPawns * pos.pawns_on_same_color_squares(Us, s)
                                     * (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));

                // Penalty for all enemy pawns x-rayed
                score -= BishopXRayPawns * popcount(attacks_bb<BISHOP>(s) & pos.pieces(Them, PAWN));

                // Bonus for bishop on a long diagonal which can "see" both center squares
                if (more_than_one(attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & Center))
                    score += LongDiagonalBishop;

                // 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 (   pos.is_chess960()
                    && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
                {
                    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;
                }
            }
        }

        if (Pt == ROOK)
        {
            // Bonus for rook on the same file as a queen
            if (file_bb(s) & pos.pieces(QUEEN))
                score += RookOnQueenFile;

            // Bonus for rook on an open or semi-open file
            if (pos.is_on_semiopen_file(Us, s))
                score += RookOnFile[pos.is_on_semiopen_file(Them, s)];

            // Penalty when trapped by the king, even more if the king cannot castle
            else if (mob <= 3)
            {
                File kf = file_of(pos.square<KING>(Us));
                if ((kf < FILE_E) == (file_of(s) < kf))
                    score -= TrappedRook * (1 + !pos.castling_rights(Us));
            }
        }

        if (Pt == QUEEN)
        {
            // Penalty if any relative pin or discovered attack against the queen
            Bitboard queenPinners;
            if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, queenPinners))
                score -= WeakQueen;

            // Bonus for queen on weak square in enemy camp
            if (relative_rank(Us, s) > RANK_4 && (~pe->pawn_attacks_span(Them) & s))
                score += QueenInfiltration;
        }
    }
    if (T)
        Trace::add(Pt, Us, score);

    return score;
  }


  // Evaluation::king() assigns bonuses and penalties to a king of a given color

  template<Tracing T> template<Color Us>
  Score Evaluation<T>::king() const {

#ifdef ANTI
    if (pos.is_anti())
        return SCORE_ZERO;
#endif
#ifdef EXTINCTION
    if (pos.is_extinction())
        return SCORE_ZERO;
#endif
#ifdef HORDE
    if (pos.is_horde() && pos.is_horde_color(Us))
        return SCORE_ZERO;
#endif
#ifdef PLACEMENT
    if (pos.is_placement() && pos.count_in_hand<KING>(Us))
        return SCORE_ZERO;
#endif

    constexpr Color    Them = ~Us;
    constexpr Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
                                           : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);

    Bitboard weak, b1, b2, b3, safe, unsafeChecks = 0;
    Bitboard rookChecks, queenChecks, bishopChecks, knightChecks;
    int kingDanger = 0;
    const Square ksq = pos.square<KING>(Us);

    // Init the score with king shelter and enemy pawns storm
    Score score = pe->king_safety<Us>(pos);

    // Attacked squares defended at most once by our queen or king
#ifdef ATOMIC
    if (pos.is_atomic())
        weak =  (attackedBy[Them][ALL_PIECES] ^ attackedBy[Them][KING])
              & ~(attackedBy[Us][ALL_PIECES] ^ attackedBy[Us][KING]);
    else
#endif
    weak =  attackedBy[Them][ALL_PIECES]
          & ~attackedBy2[Us]
          & (~attackedBy[Us][ALL_PIECES] | attackedBy[Us][KING] | attackedBy[Us][QUEEN]);

    Bitboard h = 0;
#ifdef CRAZYHOUSE
    if (pos.is_house())
        h = pos.count_in_hand<QUEEN>(Them) ? weak & ~pos.pieces() : 0;
#endif

    // Analyse the safe enemy's checks which are possible on next move
    safe  = ~pos.pieces(Them);
#ifdef ATOMIC
    if (pos.is_atomic())
        safe &= ~pos.pieces(Us) | attackedBy2[Them];
    else
#endif
    safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);

    b1 = attacks_bb<ROOK  >(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
    b2 = attacks_bb<BISHOP>(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));

    Bitboard dqko = ~attackedBy2[Us] & (attackedBy[Us][QUEEN] | attackedBy[Us][KING]);
    Bitboard dropSafe = (safe | (attackedBy[Them][ALL_PIECES] & dqko)) & ~pos.pieces(Us);

#ifdef THREECHECK
    if (pos.is_three_check() && pos.checks_given(Them))
        safe = ~pos.pieces(Them);
#endif

    // Enemy rooks checks
#ifdef CRAZYHOUSE
    h = pos.is_house() && pos.count_in_hand<ROOK>(Them) ? ~pos.pieces() : 0;
#endif
    rookChecks = b1 & (attackedBy[Them][ROOK] | (h & dropSafe)) & safe;
    if (rookChecks)
        kingDanger += SafeCheck[ROOK][more_than_one(rookChecks)];
    else
        unsafeChecks |= b1 & (attackedBy[Them][ROOK] | h);

    // Enemy queen safe checks: count them only if the checks are from squares from
    // which opponent cannot give a rook check, because rook checks are more valuable.
#ifdef CRAZYHOUSE
    h = pos.is_house() && pos.count_in_hand<QUEEN>(Them) ? ~pos.pieces() : 0;
#endif
    queenChecks =  (b1 | b2) & (attackedBy[Them][QUEEN] | (h & dropSafe)) & safe
                 & ~(attackedBy[Us][QUEEN] | rookChecks);
    if (queenChecks)
        kingDanger += SafeCheck[QUEEN][more_than_one(queenChecks)];

    // Enemy bishops checks: count them only if they are from squares from which
    // opponent cannot give a queen check, because queen checks are more valuable.
#ifdef CRAZYHOUSE
    h = pos.is_house() && pos.count_in_hand<BISHOP>(Them) ? ~pos.pieces() : 0;
#endif
    bishopChecks =  b2 & (attackedBy[Them][BISHOP] | (h & dropSafe)) & safe
                  & ~queenChecks;
    if (bishopChecks)
        kingDanger += SafeCheck[BISHOP][more_than_one(bishopChecks)];

    else
        unsafeChecks |= b2 & (attackedBy[Them][BISHOP] | (h & dropSafe));

    // Enemy knights checks
#ifdef CRAZYHOUSE
    h = pos.is_house() && pos.count_in_hand<KNIGHT>(Them) ? ~pos.pieces() : 0;
#endif
    knightChecks = attacks_bb<KNIGHT>(ksq) & (attackedBy[Them][KNIGHT] | (h & dropSafe));
    if (knightChecks & safe)
        kingDanger += SafeCheck[KNIGHT][more_than_one(knightChecks & (safe | (h & dropSafe)))];
    else
        unsafeChecks |= knightChecks & (attackedBy[Them][KNIGHT] | h);

#ifdef CRAZYHOUSE
    // Enemy pawn checks
    if (pos.is_house())
    {
        constexpr Direction Down = pawn_push(Them);
        Bitboard pawnChecks = pawn_attacks_bb<Us>(ksq);
        h = pos.count_in_hand<PAWN>(Them) ? ~pos.pieces() : 0;
        Bitboard pawnMoves = (attackedBy[Them][PAWN] & pos.pieces(Us)) | (shift<Down>(pos.pieces(Them, PAWN)) & ~pos.pieces());
        if (pawnChecks & ((pawnMoves & safe) | (h & dropSafe)))
            kingDanger += SafeCheck[PAWN][more_than_one(pawnChecks & (safe | (h & dropSafe)))];
        else
            unsafeChecks |= pawnChecks & (pawnMoves | h);
    }
#endif
#ifdef RACE
    if (pos.is_race())
        kingDanger = -kingDanger;
#endif

    // Find the squares that opponent attacks in our king flank, the squares
    // which they attack twice in that flank, and the squares that we defend.
    b1 = attackedBy[Them][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;
    b2 = b1 & attackedBy2[Them];
    b3 = attackedBy[Us][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;

    int kingFlankAttack  = popcount(b1) + popcount(b2);
    int kingFlankDefense = popcount(b3);

    const auto KDP = KingDangerParams[pos.variant()];
    kingDanger +=        kingAttackersCount[Them] * kingAttackersWeight[Them]
                 + KDP[0] * popcount(kingRing[Us] & weak)
                 + KDP[1] * popcount(unsafeChecks)
                 + KDP[2] * popcount(pos.blockers_for_king(Us))
                 + KDP[3] * kingAttacksCount[Them]
                 + KDP[4] * kingFlankAttack * kingFlankAttack / 8
                 +          mg_value(mobility[Them] - mobility[Us])
                 + KDP[5] * !pos.count<QUEEN>(Them)
                 + KDP[6] * bool(attackedBy[Us][KNIGHT] & attackedBy[Us][KING])
                 + KDP[7] * mg_value(score) / 8
                 + KDP[8] * kingFlankDefense
                 + KDP[9];
#ifdef CRAZYHOUSE
    if (pos.is_house())
    {
        kingDanger += KingDangerInHand[ALL_PIECES] * pos.count_in_hand<ALL_PIECES>(Them);
        kingDanger += KingDangerInHand[PAWN] * pos.count_in_hand<PAWN>(Them);
        kingDanger += KingDangerInHand[KNIGHT] * pos.count_in_hand<KNIGHT>(Them);
        kingDanger += KingDangerInHand[BISHOP] * pos.count_in_hand<BISHOP>(Them);
        kingDanger += KingDangerInHand[ROOK] * pos.count_in_hand<ROOK>(Them);
        kingDanger += KingDangerInHand[QUEEN] * pos.count_in_hand<QUEEN>(Them);
        h = pos.count_in_hand<QUEEN>(Them) ? weak & ~pos.pieces() : 0;
    }
#endif

    // Transform the kingDanger units into a Score, and subtract it from the evaluation
    if (kingDanger > 100)
    {
#ifdef THREECHECK
        if (pos.is_three_check())
            kingDanger = ThreeCheckKSFactors[pos.checks_given(Them)] * kingDanger / 256;
#endif
        int v = kingDanger * kingDanger / 4096;
#ifdef ATOMIC
        if (pos.is_atomic())
            v = std::min(v, (int)QueenValueMg);
#endif
#ifdef CRAZYHOUSE
        if (pos.is_house() && Us == pos.side_to_move())
            v -= v / 10;
        if (pos.is_house())
            v = std::min(v, (int)QueenValueMg);
#endif
#ifdef THREECHECK
        if (pos.is_three_check())
            v = std::min(v, (int)QueenValueMg);
#endif
        score -= make_score(v, kingDanger / 16 + KDP[10] * v / 256);
    }

    // Penalty when our king is on a pawnless flank
    if (!(pos.pieces(PAWN) & KingFlank[file_of(ksq)]))
        score -= PawnlessFlank;

    // Penalty if king flank is under attack, potentially moving toward the king
    score -= FlankAttacks[pos.variant()] * kingFlankAttack;

    if (T)
        Trace::add(KING, Us, score);

    return score;
  }


  // Evaluation::threats() assigns bonuses according to the types of the
  // attacking and the attacked pieces.

  template<Tracing T> template<Color Us>
  Score Evaluation<T>::threats() const {

    constexpr Color     Them     = ~Us;
    constexpr Direction Up       = pawn_push(Us);
    constexpr Bitboard  TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);

    Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safe;
    Score score = SCORE_ZERO;
#ifdef ANTI
    if (pos.is_anti())
    {
        constexpr Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
        bool weCapture = attackedBy[Us][ALL_PIECES] & pos.pieces(Them);
        bool theyCapture = attackedBy[Them][ALL_PIECES] & pos.pieces(Us);

        // Penalties for possible captures
        if (weCapture)
        {
            // Penalty if we only attack unprotected pieces
            bool theyDefended = attackedBy[Us][ALL_PIECES] & pos.pieces(Them) & attackedBy[Them][ALL_PIECES];
            for (PieceType pt = PAWN; pt <= KING; ++pt)
            {
                if (attackedBy[Us][pt] & pos.pieces(Them) & ~attackedBy2[Us])
                    score -= AttacksAnti[theyCapture][theyDefended][pt];
                else if (attackedBy[Us][pt] & pos.pieces(Them))
                    score -= AttacksAnti[theyCapture][theyDefended][NO_PIECE_TYPE];
            }
            // If both colors attack pieces, increase penalty with piece count
            if (theyCapture)
                score -= PieceCountAnti * pos.count<ALL_PIECES>(Us);
        }
        // Bonus if we threaten to force captures (ignoring possible discoveries)
        if (!weCapture || theyCapture)
        {
            b = pos.pieces(Us, PAWN);
            Bitboard pawnPushes = shift<Up>(b | (shift<Up>(b & TRank2BB) & ~pos.pieces())) & ~pos.pieces();
            Bitboard pieceMoves = (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP] | attackedBy[Us][ROOK]
                                 | attackedBy[Us][QUEEN] | attackedBy[Us][KING]) & ~pos.pieces();
            Bitboard unprotectedPawnPushes = pawnPushes & ~attackedBy[Us][ALL_PIECES];
            Bitboard unprotectedPieceMoves = pieceMoves & ~attackedBy2[Us];

            score += ThreatsAnti[0] * popcount(attackedBy[Them][ALL_PIECES] & (pawnPushes | pieceMoves));
            score += ThreatsAnti[1] * popcount(attackedBy[Them][ALL_PIECES] & (unprotectedPawnPushes | unprotectedPieceMoves));
        }
    }
    else
#endif
#ifdef GRID
    if (pos.is_grid()) {} else
#endif
#ifdef LOSERS
    if (pos.is_losers())
    {
        constexpr Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
        bool weCapture = attackedBy[Us][ALL_PIECES] & pos.pieces(Them);
        bool theyCapture = attackedBy[Them][ALL_PIECES] & pos.pieces(Us);

        // Penalties for possible captures
        if (weCapture)
        {
            // Penalty if we only attack unprotected pieces
            bool theyDefended = attackedBy[Us][ALL_PIECES] & pos.pieces(Them) & attackedBy[Them][ALL_PIECES];
            for (PieceType pt = PAWN; pt <= KING; ++pt)
            {
                if (attackedBy[Us][pt] & pos.pieces(Them) & ~attackedBy2[Us])
                    score -= AttacksLosers[theyCapture][theyDefended][pt];
                else if (attackedBy[Us][pt] & pos.pieces(Them))
                    score -= AttacksLosers[theyCapture][theyDefended][NO_PIECE_TYPE];
            }
        }
        // Bonus if we threaten to force captures (ignoring possible discoveries)
        if (!weCapture || theyCapture)
        {
            b = pos.pieces(Us, PAWN);
            Bitboard pawnPushes = shift<Up>(b | (shift<Up>(b & TRank2BB) & ~pos.pieces())) & ~pos.pieces();
            Bitboard pieceMoves = (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP] | attackedBy[Us][ROOK]
                                 | attackedBy[Us][QUEEN] | attackedBy[Us][KING]) & ~pos.pieces();
            Bitboard unprotectedPawnPushes = pawnPushes & ~attackedBy[Us][ALL_PIECES];
            Bitboard unprotectedPieceMoves = pieceMoves & ~attackedBy2[Us];

            score += ThreatsLosers[0] * popcount(attackedBy[Them][ALL_PIECES] & (pawnPushes | pieceMoves));
            score += ThreatsLosers[1] * popcount(attackedBy[Them][ALL_PIECES] & (unprotectedPawnPushes | unprotectedPieceMoves));
        }
    }
    else
#endif
    switch (pos.variant())
    {
#ifdef ATOMIC
    case ATOMIC_VARIANT:
        b = pos.pieces(Them) & attackedBy[Us][ALL_PIECES] & ~attackedBy[Us][KING];
        while (b)
        {
            Square s = pop_lsb(&b);
            Bitboard blast = (attacks_bb<KING>(s) & (pos.pieces() ^ pos.pieces(PAWN))) | s;
            int count = popcount(blast & pos.pieces(Them)) - popcount(blast & pos.pieces(Us)) - 1;
            if (blast & pos.pieces(Them, KING, QUEEN))
                count++;
            if ((blast & pos.pieces(Us, QUEEN)) || ((attackedBy[Us][QUEEN] & s) & ~attackedBy2[Us]))
                count--;
            score += std::max(SCORE_ZERO, ThreatByBlast * count);
        }
    break;
#endif
    default:

    // Non-pawn enemies
    nonPawnEnemies = pos.pieces(Them) & ~pos.pieces(PAWN);

    // Squares strongly protected by the enemy, either because they defend the
    // square with a pawn, or because they defend the square twice and we don't.
    stronglyProtected =  attackedBy[Them][PAWN]
                       | (attackedBy2[Them] & ~attackedBy2[Us]);

    // Non-pawn enemies, strongly protected
    defended = nonPawnEnemies & stronglyProtected;

    // Enemies not strongly protected and under our attack
    weak = pos.pieces(Them) & ~stronglyProtected & attackedBy[Us][ALL_PIECES];

    // Bonus according to the kind of attacking pieces
    if (defended | weak)
    {
        b = (defended | weak) & (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP]);
        while (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)))];

        if (weak & attackedBy[Us][KING])
            score += ThreatByKing;

        b =  ~attackedBy[Them][ALL_PIECES]
           | (nonPawnEnemies & attackedBy2[Us]);
        score += Hanging * popcount(weak & b);

        // Additional bonus if weak piece is only protected by a queen
        score += WeakQueenProtection * popcount(weak & attackedBy[Them][QUEEN]);
    }

    // Bonus for restricting their piece moves
    b =   attackedBy[Them][ALL_PIECES]
       & ~stronglyProtected
       &  attackedBy[Us][ALL_PIECES];
    score += RestrictedPiece * popcount(b);

    // Protected or unattacked squares
    safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];

    // Bonus for attacking enemy pieces with our relatively safe pawns
    b = pos.pieces(Us, PAWN) & safe;
    b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
    score += ThreatBySafePawn * popcount(b);

    // Find squares where our pawns can push on the next move
    b  = shift<Up>(pos.pieces(Us, PAWN)) & ~pos.pieces();
    b |= shift<Up>(b & TRank3BB) & ~pos.pieces();

    // Keep only the squares which are relatively safe
    b &= ~attackedBy[Them][PAWN] & safe;

    // Bonus for safe pawn threats on the next move
    b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
    score += ThreatByPawnPush * popcount(b);

    // Bonus for threats on the next moves against enemy queen
#ifdef CRAZYHOUSE
    if ((pos.is_house() ? pos.count<QUEEN>(Them) - pos.count_in_hand<QUEEN>(Them) : pos.count<QUEEN>(Them)) == 1)
#else
    if (pos.count<QUEEN>(Them) == 1)
#endif
    {
        bool queenImbalance = pos.count<QUEEN>() == 1;

        Square s = pos.square<QUEEN>(Them);
        safe =   mobilityArea[Us]
              & ~pos.pieces(Us, PAWN)
              & ~stronglyProtected;

        b = attackedBy[Us][KNIGHT] & attacks_bb<KNIGHT>(s);

        score += KnightOnQueen * popcount(b & safe) * (1 + queenImbalance);

        b =  (attackedBy[Us][BISHOP] & attacks_bb<BISHOP>(s, pos.pieces()))
           | (attackedBy[Us][ROOK  ] & attacks_bb<ROOK  >(s, pos.pieces()));

        score += SliderOnQueen * popcount(b & safe & attackedBy2[Us]) * (1 + queenImbalance);
    }
    }

    if (T)
        Trace::add(THREAT, Us, score);

    return score;
  }

  // Evaluation::passed() evaluates the passed pawns and candidate passed
  // pawns of the given color.

  template<Tracing T> template<Color Us>
  Score Evaluation<T>::passed() const {

    constexpr Color     Them = ~Us;
    constexpr Direction Up   = pawn_push(Us);
    constexpr Direction Down = -Up;

    auto king_proximity = [&](Color c, Square s) {
      return std::min(distance(pos.square<KING>(c), s), 5);
    };

    Bitboard b, bb, squaresToQueen, unsafeSquares, blockedPassers, helpers;
    Score score = SCORE_ZERO;

    b = pe->passed_pawns(Us);

    blockedPassers = b & shift<Down>(pos.pieces(Them, PAWN));
    if (blockedPassers)
    {
        helpers =  shift<Up>(pos.pieces(Us, PAWN))
                 & ~pos.pieces(Them)
                 & (~attackedBy2[Them] | attackedBy[Us][ALL_PIECES]);

        // Remove blocked candidate passers that don't have help to pass
        b &=  ~blockedPassers
            | shift<WEST>(helpers)
            | shift<EAST>(helpers);
    }

    while (b)
    {
        Square s = pop_lsb(&b);

        assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));

        int r = relative_rank(Us, s);

        Score bonus = PassedRank[pos.variant()][r];

#ifdef GRID
        if (pos.is_grid()) {} else
#endif
        if (r > RANK_3)
        {
            int w = 5 * r - 13;
            Square blockSq = s + Up;
#ifdef HORDE
            if (pos.is_horde())
            {
                // Assume a horde king distance of approximately 5
                if (pos.is_horde_color(Us))
                    bonus += make_score(0, king_proximity(Them, blockSq) * 5 * w);
                else
                    bonus += make_score(0, 15 * w);
            }
            else
#endif
#ifdef PLACEMENT
            if (pos.is_placement() && pos.count_in_hand<KING>(Us))
                bonus += make_score(0, 15 * w);
            else
#endif
#ifdef ANTI
            if (pos.is_anti()) {} else
#endif
#ifdef ATOMIC
            if (pos.is_atomic())
                bonus += make_score(0, king_proximity(Them, blockSq) * 5 * w);
            else
#endif
            {
            // Adjust bonus based on the king's proximity
            bonus += make_score(0, (  (king_proximity(Them, blockSq) * 19) / 4
                                     - king_proximity(Us,   blockSq) *  2) * w);

            // If blockSq is not the queening square then consider also a second push
            if (r != RANK_7)
                bonus -= make_score(0, king_proximity(Us, blockSq + Up) * w);
            }

            // If the pawn is free to advance, then increase the bonus
            if (pos.empty(blockSq))
            {
                squaresToQueen = forward_file_bb(Us, s);
                unsafeSquares = passed_pawn_span(Us, s);

                bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN);

                if (!(pos.pieces(Them) & bb))
                    unsafeSquares &= attackedBy[Them][ALL_PIECES];

                // If there are no enemy attacks on passed pawn span, assign a big bonus.
                // Otherwise assign a smaller bonus if the path to queen is not attacked
                // and even smaller bonus if it is attacked but block square is not.
                int k = !unsafeSquares                    ? 35 :
                        !(unsafeSquares & squaresToQueen) ? 20 :
                        !(unsafeSquares & blockSq)        ?  9 :
                                                             0 ;

                // Assign a larger bonus if the block square is defended
                if ((pos.pieces(Us) & bb) || (attackedBy[Us][ALL_PIECES] & blockSq))
                    k += 5;

                bonus += make_score(k * w, k * w);
            }
        } // r > RANK_3

        score += bonus - PassedFile * edge_distance(file_of(s));
    }

    if (T)
        Trace::add(PASSED, Us, score);

    return score;
  }


  // Evaluation::space() computes a space evaluation for a given side, aiming to improve game
  // play in the opening. It is based on the number of safe squares on the 4 central files
  // on ranks 2 to 4. Completely safe squares behind a friendly pawn are counted twice.
  // Finally, the space bonus is multiplied by a weight which decreases according to occupancy.

  template<Tracing T> template<Color Us>
  Score Evaluation<T>::space() const {

    // Early exit if, for example, both queens or 6 minor pieces have been exchanged
    if (pos.non_pawn_material() < SpaceThreshold[pos.variant()])
        return SCORE_ZERO;

    constexpr Color Them     = ~Us;
    constexpr Direction Down = -pawn_push(Us);
    constexpr Bitboard SpaceMask =
      Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB)
                  : CenterFiles & (Rank7BB | Rank6BB | Rank5BB);

    // Find the available squares for our pieces inside the area defined by SpaceMask
    Bitboard safe =   SpaceMask
                   & ~pos.pieces(Us, PAWN)
                   & ~attackedBy[Them][PAWN];

    // Find all squares which are at most three squares behind some friendly pawn
    Bitboard behind = pos.pieces(Us, PAWN);
    behind |= shift<Down>(behind);
    behind |= shift<Down+Down>(behind);

    int bonus = popcount(safe) + popcount(behind & safe & ~attackedBy[Them][ALL_PIECES]);
    int weight = pos.count<ALL_PIECES>(Us) - 3 + std::min(pe->blocked_count(), 9);
    Score score = make_score(bonus * weight * weight / 16, 0);
#ifdef KOTH
    if (pos.is_koth())
        score += KothSafeCenter * popcount(behind & safe & Center);
#endif

    if (T)
        Trace::add(SPACE, Us, score);

    return score;
  }

  // Evaluation::variant() computes variant-specific evaluation terms.

  template<Tracing T> template<Color Us>
  Score Evaluation<T>::variant() const {

    constexpr Color Them = (Us == WHITE ? BLACK : WHITE);

    Score score = SCORE_ZERO;

#ifdef ATOMIC
    if (pos.is_atomic())
        score -= AtomicConfinedKing * popcount(attackedBy[Us][KING] & pos.pieces());
#endif
#ifdef HORDE
    if (pos.is_horde() && pos.is_horde_color(Them))
    {
        // Add a bonus according to how close we are to breaking through the pawn wall
        if (pos.pieces(Us, ROOK) | pos.pieces(Us, QUEEN))
        {
            int dist = 8;
            if ((attackedBy[Us][QUEEN] | attackedBy[Us][ROOK]) & rank_bb(relative_rank(Us, RANK_8)))
                dist = 0;
            else for (File f = FILE_A; f <= FILE_H; ++f)
            {
                int pawns = popcount(pos.pieces(Them, PAWN) & file_bb(f));
                int pawnsl = std::min(popcount(pos.pieces(Them, PAWN) & shift<WEST>(file_bb(f))), pawns);
                int pawnsr = std::min(popcount(pos.pieces(Them, PAWN) & shift<EAST>(file_bb(f))), pawns);
                dist = std::min(dist, pawnsl + pawnsr);
            }
            score += HordeShelter * pos.count<PAWN>(Them) / (1 + dist) / (pos.pieces(Us, QUEEN) ? 2 : 4);
        }
    }
#endif
#ifdef KOTH
    if (pos.is_koth())
    {
        // Pinned piece (not pawn) attacks are not included in attackedBy
        constexpr Direction Up = pawn_push(Us);
        Bitboard pinned = pos.blockers_for_king(Them) & pos.pieces(Them);
        Bitboard center = Center;
        while (center)
        {
            // Skip costly attackers_to if the center is not attacked by them
            Square s = pop_lsb(&center);
            int dist = distance(pos.square<KING>(Us), s)
                      + ((pinned || (attackedBy[Them][ALL_PIECES] & s)) ? popcount(pos.attackers_to(s) & pos.pieces(Them)) : 0)
                      + !!(pos.pieces(Us) & s)
                      + !!(shift<Up>(pos.pieces(Us, PAWN) & s) & pos.pieces(Them, PAWN));
            assert(dist > 0);
            score += KothDistanceBonus[std::min(dist - 1, 5)];
        }
    }
#endif
#ifdef RACE
    if (pos.is_race())
    {
        Square ksq = pos.square<KING>(Us);
        int s = relative_rank(BLACK, ksq);
        Bitboard b = file_bb(ksq);
        for (Rank kr = rank_of(ksq), r = Rank(kr + 1); r <= RANK_8; ++r)
        {
            b |= shift<EAST>(b) | shift<WEST>(b);
            if (!(rank_bb(r) & b & ~attackedBy[Them][ALL_PIECES]))
                s++;
        }
        score += KingRaceBonus[std::min(s, 7)];
    }
#endif
#ifdef THREECHECK
    if (pos.is_three_check())
        score += ChecksGivenBonus[pos.checks_given(Us)];
#endif

    if (T)
        Trace::add(VARIANT, Us, score);

    return score;
  }


  // Evaluation::winnable() adjusts the midgame and endgame score components, based on
  // the known attacking/defending status of the players. The final value is derived
  // by interpolation from the midgame and endgame values.

  template<Tracing T>
  Value Evaluation<T>::winnable(Score score) const {

    int complexity = 0;

#ifdef ANTI
    if (pos.is_anti()) {} else
#endif
#ifdef HORDE
    if (pos.is_horde()) {} else
#endif
#ifdef PLACEMENT
    if (pos.is_placement() && (pos.count_in_hand<KING>(WHITE) || pos.count_in_hand<KING>(BLACK))) {} else
#endif
#ifdef LOSERS
    if (pos.is_losers()) {} else
#endif
    {
    int outflanking =  distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
                     - distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));

    bool pawnsOnBothFlanks =   (pos.pieces(PAWN) & QueenSide)
                            && (pos.pieces(PAWN) & KingSide);

    bool almostUnwinnable =   outflanking < 0
                           && !pawnsOnBothFlanks;

    bool infiltration =   rank_of(pos.square<KING>(WHITE)) > RANK_4
                       || rank_of(pos.square<KING>(BLACK)) < RANK_5;

    // Compute the initiative bonus for the attacking side
    complexity =   9 * pe->passed_count()
                    + 12 * pos.count<PAWN>()
                    +  9 * outflanking
                    + 21 * pawnsOnBothFlanks
                    + 24 * infiltration
                    + 51 * !pos.non_pawn_material()
                    - 43 * almostUnwinnable
                    -110 ;
    }

    Value mg = mg_value(score);
    Value eg = eg_value(score);

    // Now apply the bonus: note that we find the attacking side by extracting the
    // sign of the midgame or endgame values, and that we carefully cap the bonus
    // so that the midgame and endgame scores do not change sign after the bonus.
    int u = ((mg > 0) - (mg < 0)) * Utility::clamp(complexity + 50, -abs(mg), 0);
    int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));

    mg += u;
    eg += v;

    // Compute the scale factor for the winning side
    Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
    int sf = me->scale_factor(pos, strongSide);

#ifdef ANTI
    if (pos.is_anti()) {} else
#endif
#ifdef EXTINCTION
    if (pos.is_extinction()) {} else
#endif
#ifdef PLACEMENT
    if (pos.is_placement() && pos.count_in_hand<KING>(~strongSide)) {} else
#endif
#ifdef ATOMIC
    if (pos.is_atomic())
    {
        if (   pos.non_pawn_material(~strongSide) <= RookValueMg
            && pos.count<PAWN>(WHITE) == pos.count<PAWN>(BLACK))
            sf = std::max(0, sf - pos.rule50_count() / 2);
    }
    else
#endif
#ifdef HORDE
    if (pos.is_horde() && pos.is_horde_color(~strongSide))
    {
        if (pos.non_pawn_material(~strongSide) >= QueenValueMg)
            sf = 10;
    }
    else
#endif
    // If scale factor is not already specific, scale down via general heuristics
    if (sf == SCALE_FACTOR_NORMAL)
    {
        if (pos.opposite_bishops())
        {
            if (   pos.non_pawn_material(WHITE) == BishopValueMg
                && pos.non_pawn_material(BLACK) == BishopValueMg)
                sf = 18 + 4 * popcount(pe->passed_pawns(strongSide));
            else
                sf = 22 + 3 * pos.count<ALL_PIECES>(strongSide);
        }
        else if (  pos.non_pawn_material(WHITE) == RookValueMg
                && pos.non_pawn_material(BLACK) == RookValueMg
                && pos.count<PAWN>(strongSide) - pos.count<PAWN>(~strongSide) <= 1
                && bool(KingSide & pos.pieces(strongSide, PAWN)) != bool(QueenSide & pos.pieces(strongSide, PAWN))
                && (attacks_bb<KING>(pos.square<KING>(~strongSide)) & pos.pieces(~strongSide, PAWN)))
            sf = 36;
        else if (pos.count<QUEEN>() == 1)
            sf = 37 + 3 * (pos.count<QUEEN>(WHITE) == 1 ? pos.count<BISHOP>(BLACK) + pos.count<KNIGHT>(BLACK)
                                                        : pos.count<BISHOP>(WHITE) + pos.count<KNIGHT>(WHITE));
        else
            sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide));
    }

    // Interpolate between the middlegame and (scaled by 'sf') endgame score
    v =  mg * int(me->game_phase())
       + eg * int(PHASE_MIDGAME - me->game_phase()) * ScaleFactor(sf) / SCALE_FACTOR_NORMAL;
    v /= PHASE_MIDGAME;

    if (T)
    {
        Trace::add(WINNABLE, make_score(u, eg * ScaleFactor(sf) / SCALE_FACTOR_NORMAL - eg_value(score)));
        Trace::add(TOTAL, make_score(mg, eg * ScaleFactor(sf) / SCALE_FACTOR_NORMAL));
    }

    return Value(v);
  }


  // Evaluation::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.

  template<Tracing T>
  Value Evaluation<T>::value() {

    assert(!pos.checkers());

    if (pos.is_variant_end())
        return pos.variant_result();

    // Probe the material hash table
    me = Material::probe(pos);

    // If we have a specialized evaluation function for the current material
    // configuration, call it and return.
    if (me->specialized_eval_exists())
        return me->evaluate(pos);

    // Initialize score by reading the incrementally updated scores included in
    // the position object (material + piece square tables) and the material
    // imbalance. Score is computed internally from the white point of view.
    Score score = pos.psq_score() + me->imbalance() + pos.this_thread()->contempt;

    // Probe the pawn hash table
    pe = Pawns::probe(pos);
    score += pe->pawn_score(WHITE) - pe->pawn_score(BLACK);

    // 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;
    };

    if (pos.variant() == CHESS_VARIANT)
    if (lazy_skip(LazyThreshold1))
        goto make_v;

    // Main evaluation begins here
    initialize<WHITE>();
    initialize<BLACK>();

    // Pieces evaluated first (also populates attackedBy, attackedBy2).
    // Note that the order of evaluation of the terms is left unspecified.
    score +=  pieces<WHITE, KNIGHT>() - pieces<BLACK, KNIGHT>()
            + pieces<WHITE, BISHOP>() - pieces<BLACK, BISHOP>()
            + pieces<WHITE, ROOK  >() - pieces<BLACK, ROOK  >()
            + pieces<WHITE, QUEEN >() - pieces<BLACK, QUEEN >();

#ifdef CRAZYHOUSE
    if (pos.is_house()) {
        // Positional bonus for potential drop points - unoccupied squares in enemy territory that are not attacked by enemy non-KQ pieces
        mobility[WHITE] += DropMobilityBonus * popcount(~(attackedBy[BLACK][PAWN] | attackedBy[BLACK][KNIGHT] | attackedBy[BLACK][BISHOP] | attackedBy[BLACK][ROOK] | pos.pieces() | Rank1BB | Rank2BB | Rank3BB | Rank4BB));
        mobility[BLACK] += DropMobilityBonus * popcount(~(attackedBy[WHITE][PAWN] | attackedBy[WHITE][KNIGHT] | attackedBy[WHITE][BISHOP] | attackedBy[WHITE][ROOK] | pos.pieces() | Rank5BB | Rank6BB | Rank7BB | Rank8BB));
    }
#endif

    score += mobility[WHITE] - mobility[BLACK];

    // More complex interactions that require fully populated attack bitboards
    score +=  king<   WHITE>() - king<   BLACK>()
            + passed< WHITE>() - passed< BLACK>();

    if (pos.variant() == CHESS_VARIANT)
    if (lazy_skip(LazyThreshold2))
        goto make_v;

    score +=  threats<WHITE>() - threats<BLACK>()
            + space<  WHITE>() - space<  BLACK>();

    if (pos.variant() != CHESS_VARIANT)
        score += variant<WHITE>() - variant<BLACK>();
make_v:
    // Derive single value from mg and eg parts of score
    Value v = winnable(score);

    // In case of tracing add all remaining individual evaluation terms
    if (T)
    {
        Trace::add(MATERIAL, pos.psq_score());
        Trace::add(IMBALANCE, me->imbalance());
        Trace::add(PAWN, pe->pawn_score(WHITE), pe->pawn_score(BLACK));
        Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
    }

    // Evaluation grain
    v = (v / 16) * 16;

    // Side to move point of view
    v = (pos.side_to_move() == WHITE ? v : -v) + Tempo;

    // Damp down the evaluation linearly when shuffling
    v = v * (100 - pos.rule50_count()) / 100;

    return v;
  }

} // namespace


/// evaluate() is the evaluator for the outer world. It returns a static
/// evaluation of the position from the point of view of the side to move.

Value Eval::evaluate(const Position& pos) {
  return Evaluation<NO_TRACE>(pos).value();
}


/// 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) {

  if (pos.checkers())
      return "Total evaluation: none (in check)";

  std::memset(scores, 0, sizeof(scores));

  pos.this_thread()->contempt = SCORE_ZERO; // Reset any dynamic contempt

  Value v = Evaluation<TRACE>(pos).value();

  v = pos.side_to_move() == WHITE ? v : -v; // Trace scores are from white's point of view

  std::stringstream ss;
  ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
     << "     Term    |    White    |    Black    |    Total   \n"
     << "             |   MG    EG  |   MG    EG  |   MG    EG \n"
     << " ------------+-------------+-------------+------------\n"
     << "    Material | " << Term(MATERIAL)
     << "   Imbalance | " << Term(IMBALANCE)
     << "       Pawns | " << Term(PAWN)
     << "     Knights | " << Term(KNIGHT)
     << "     Bishops | " << Term(BISHOP)
     << "       Rooks | " << Term(ROOK)
     << "      Queens | " << Term(QUEEN)
     << "    Mobility | " << Term(MOBILITY)
     << " King safety | " << Term(KING)
     << "     Threats | " << Term(THREAT)
     << "      Passed | " << Term(PASSED)
     << "       Space | " << Term(SPACE)
     << "    Winnable | " << Term(WINNABLE)
     << "     Variant | " << Term(VARIANT)
     << " ------------+-------------+-------------+------------\n"
     << "       Total | " << Term(TOTAL);

  ss << "\nFinal evaluation: " << to_cp(v) << " (white side)\n";

  return ss.str();
}