Prefer template to name decoration
[stockfish] / src / evaluate.cpp
index 12542af09f5b63cdb1f25c29344596a331a22f19..4bda8466e1fdaeddc3e346376d4a37f2a038dbae 100644 (file)
@@ -6,12 +6,12 @@
   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.
-  
+
   Glaurung 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/>.
 */
@@ -63,6 +63,7 @@ namespace {
   const int WeightPassedPawnsMidgameInternal   = 0x100;
   const int WeightPassedPawnsEndgameInternal   = 0x100;
   const int WeightKingSafetyInternal           = 0x100;
+  const int WeightKingOppSafetyInternal        = 0x100;
 
   // Visually better to define tables constants
   typedef Value V;
@@ -105,7 +106,7 @@ namespace {
   //    8       9     10     11     12     13     14     15
     V( 24), V( 27), V(28), V(29), V(30), V(31), V(32), V(33)
   };
-  
+
   const Value EndgameRookMobilityBonus[] = {
   //    0       1      2      3      4      5      6      7
     V(-30), V(-18), V(-6),  V(6), V(18), V(30), V(42), V(54),
@@ -200,7 +201,7 @@ namespace {
     ((1ULL << SQ_A1) | (1ULL << SQ_H1)),
     ((1ULL << SQ_A8) | (1ULL << SQ_H8))
   };
-  
+
   /// King safety constants and variables.  The king safety scores are taken
   /// from the array SafetyTable[].  Various little "meta-bonuses" measuring
   /// the strength of the attack are added up into an integer, which is used
@@ -212,7 +213,7 @@ namespace {
   const int BishopAttackWeight = 2;
   const int KnightAttackWeight = 2;
 
-  // Bonuses for safe checks for each piece type.  
+  // Bonuses for safe checks for each piece type.
   int QueenContactCheckBonus = 4;
   int RookContactCheckBonus  = 2;
   int QueenCheckBonus        = 2;
@@ -268,12 +269,13 @@ namespace {
   void evaluate_trapped_bishop_a1h1(const Position &pos, Square s, Color us,
                                     EvalInfo &ei);
 
-  Value apply_weight(Value v, int w);
-  Value scale_by_game_phase(Value mv, Value ev, Phase ph, ScaleFactor sf[]);
+  inline Value apply_weight(Value v, int w);
+  Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]);
 
   int count_1s_8bit(Bitboard b);
 
   int compute_weight(int uciWeight, int internalWeight);
+  int weight_option(const std::string& opt, int weight);
   void init_safety();
 
 }
@@ -288,141 +290,122 @@ namespace {
 /// between them based on the remaining material.
 
 Value evaluate(const Position &pos, EvalInfo &ei, int threadID) {
-  Color stm;
-  Square s;
-  ScaleFactor factor[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL};
-  Phase phase;
-
-  memset(&ei, 0, sizeof(EvalInfo));
 
   assert(pos.is_ok());
   assert(threadID >= 0 && threadID < THREAD_MAX);
 
-  stm = pos.side_to_move();
+  memset(&ei, 0, sizeof(EvalInfo));
 
   // Initialize by reading the incrementally updated scores included in the
-  // position object (material + piece square tables):
+  // position object (material + piece square tables)
   ei.mgValue = pos.mg_value();
   ei.egValue = pos.eg_value();
 
-  // Probe the material hash table:
+  // Probe the material hash table
   ei.mi = MaterialTable[threadID]->get_material_info(pos);
   ei.mgValue += ei.mi->mg_value();
   ei.egValue += ei.mi->eg_value();
 
-  factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
-  factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
-
   // If we have a specialized evaluation function for the current material
-  // configuration, call it and return:
-  if(ei.mi->specialized_eval_exists())
-    return ei.mi->evaluate(pos);
+  // configuration, call it and return
+  if (ei.mi->specialized_eval_exists())
+      return ei.mi->evaluate(pos);
 
-  phase = pos.game_phase();
+  // After get_material_info() call that modifies them
+  ScaleFactor factor[2];
+  factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
+  factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
 
-  // Probe the pawn hash table:
+  // Probe the pawn hash table
   ei.pi = PawnTable[threadID]->get_pawn_info(pos);
   ei.mgValue += apply_weight(ei.pi->mg_value(), WeightPawnStructureMidgame);
   ei.egValue += apply_weight(ei.pi->eg_value(), WeightPawnStructureEndgame);
 
-  // Initialize king attack bitboards and king attack zones for both sides:
-  ei.attackedBy[WHITE][KING] = pos.king_attacks(pos.king_square(WHITE));
-  ei.attackedBy[BLACK][KING] = pos.king_attacks(pos.king_square(BLACK));
-  ei.attackZone[WHITE] =
-    ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8);
-  ei.attackZone[BLACK] =
-    ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8);
-
-  // Initialize pawn attack bitboards for both sides:
-  ei.attackedBy[WHITE][PAWN] =
-    ((pos.pawns(WHITE) << 9) & ~FileABB) | ((pos.pawns(WHITE) << 7) & ~FileHBB);
-  ei.attackCount[WHITE] +=
-    count_1s_max_15(ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING])/2;
-  ei.attackedBy[BLACK][PAWN] =
-    ((pos.pawns(BLACK) >> 7) & ~FileABB) | ((pos.pawns(BLACK) >> 9) & ~FileHBB);
-  ei.attackCount[BLACK] +=
-    count_1s_max_15(ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING])/2;
-
-  // Evaluate pieces:
-  for(Color c = WHITE; c <= BLACK; c++) {
-    Bitboard b;
+  // Initialize king attack bitboards and king attack zones for both sides
+  ei.attackedBy[WHITE][KING] = pos.piece_attacks<KING>(pos.king_square(WHITE));
+  ei.attackedBy[BLACK][KING] = pos.piece_attacks<KING>(pos.king_square(BLACK));
+  ei.kingZone[WHITE] = ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8);
+  ei.kingZone[BLACK] = ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8);
+
+  // Initialize pawn attack bitboards for both sides
+  ei.attackedBy[WHITE][PAWN] = ((pos.pawns(WHITE) << 9) & ~FileABB) | ((pos.pawns(WHITE) << 7) & ~FileHBB);
+  ei.attackedBy[BLACK][PAWN] = ((pos.pawns(BLACK) >> 7) & ~FileABB) | ((pos.pawns(BLACK) >> 9) & ~FileHBB);
+  ei.kingAttackersCount[WHITE] = count_1s_max_15(ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING])/2;
+  ei.kingAttackersCount[BLACK] = count_1s_max_15(ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING])/2;
 
+  // Evaluate pieces
+  for (Color c = WHITE; c <= BLACK; c++)
+  {
     // Knights
-    for(int i = 0; i < pos.knight_count(c); i++) {
-      s = pos.knight_list(c, i);
-      evaluate_knight(pos, s, c, ei);
-    }
-    
+    for (int i = 0; i < pos.knight_count(c); i++)
+        evaluate_knight(pos, pos.knight_list(c, i), c, ei);
+
     // Bishops
-    for(int i = 0; i < pos.bishop_count(c); i++) {
-      s = pos.bishop_list(c, i);
-      evaluate_bishop(pos, s, c, ei);
-    }
+    for (int i = 0; i < pos.bishop_count(c); i++)
+        evaluate_bishop(pos, pos.bishop_list(c, i), c, ei);
 
     // Rooks
-    for(int i = 0; i < pos.rook_count(c); i++) {
-      s = pos.rook_list(c, i);
-      evaluate_rook(pos, s, c, ei);
-    }
+    for (int i = 0; i < pos.rook_count(c); i++)
+        evaluate_rook(pos, pos.rook_list(c, i), c, ei);
 
     // Queens
-    for(int i = 0; i < pos.queen_count(c); i++) {
-      s = pos.queen_list(c, i);
-      evaluate_queen(pos, s, c, ei);
-    }
+    for(int i = 0; i < pos.queen_count(c); i++)
+        evaluate_queen(pos, pos.queen_list(c, i), c, ei);
 
-    // Some special patterns:
-
-    // Trapped bishops on a7/h7/a2/h2
-    b = pos.bishops(c) & MaskA7H7[c];
-    while(b) {
-      s = pop_1st_bit(&b);
-      evaluate_trapped_bishop_a7h7(pos, s, c, ei);
+    // Special pattern: trapped bishops on a7/h7/a2/h2
+    Bitboard b = pos.bishops(c) & MaskA7H7[c];
+    while (b)
+    {
+        Square s = pop_1st_bit(&b);
+        evaluate_trapped_bishop_a7h7(pos, s, c, ei);
     }
 
-    // Trapped bishops on a1/h1/a8/h8 in Chess960:
-    if(Chess960) {
-      b = pos.bishops(c) & MaskA1H1[c];
-      while(b) {
-        s = pop_1st_bit(&b);
-        evaluate_trapped_bishop_a1h1(pos, s, c, ei);
-      }
+    // Special pattern: trapped bishops on a1/h1/a8/h8 in Chess960:
+    if (Chess960)
+    {
+        b = pos.bishops(c) & MaskA1H1[c];
+        while (b)
+        {
+            Square s = pop_1st_bit(&b);
+            evaluate_trapped_bishop_a1h1(pos, s, c, ei);
+        }
     }
 
-    ei.attackedBy[c][0] =
-      ei.attackedBy[c][PAWN] | ei.attackedBy[c][KNIGHT] 
-      | ei.attackedBy[c][BISHOP] | ei.attackedBy[c][ROOK] 
-      | ei.attackedBy[c][QUEEN] | ei.attackedBy[c][KING];
+    // Sum up all attacked squares
+    ei.attackedBy[c][0] =   ei.attackedBy[c][PAWN]   | ei.attackedBy[c][KNIGHT]
+                          | ei.attackedBy[c][BISHOP] | ei.attackedBy[c][ROOK]
+                          | ei.attackedBy[c][QUEEN]  | ei.attackedBy[c][KING];
   }
 
   // Kings.  Kings are evaluated after all other pieces for both sides,
   // because we need complete attack information for all pieces when computing
   // the king safety evaluation.
-  for(Color c = WHITE; c <= BLACK; c++) {
-    s = pos.king_square(c);
-    evaluate_king(pos, s, c, ei);
-  }
+  for (Color c = WHITE; c <= BLACK; c++)
+      evaluate_king(pos, pos.king_square(c), c, ei);
 
   // Evaluate passed pawns.  We evaluate passed pawns for both sides at once,
   // because we need to know which side promotes first in positions where
   // both sides have an unstoppable passed pawn.
-  if(ei.pi->passed_pawns())
-    evaluate_passed_pawns(pos, ei);
+  if (ei.pi->passed_pawns())
+      evaluate_passed_pawns(pos, ei);
 
-  // Middle-game specific evaluation terms
-  if(phase > PHASE_ENDGAME) {
+  Phase phase = pos.game_phase();
 
+  // Middle-game specific evaluation terms
+  if (phase > PHASE_ENDGAME)
+  {
     // Pawn storms in positions with opposite castling.
-    if(square_file(pos.king_square(WHITE)) >= FILE_E &&
-       square_file(pos.king_square(BLACK)) <= FILE_D)
-      ei.mgValue +=
-        ei.pi->queenside_storm_value(WHITE) -
-        ei.pi->kingside_storm_value(BLACK);
-    else if(square_file(pos.king_square(WHITE)) <= FILE_D &&
-            square_file(pos.king_square(BLACK)) >= FILE_E)
-      ei.mgValue += 
-        ei.pi->kingside_storm_value(WHITE) -
-        ei.pi->queenside_storm_value(BLACK);
+    if (   square_file(pos.king_square(WHITE)) >= FILE_E
+        && square_file(pos.king_square(BLACK)) <= FILE_D)
+
+        ei.mgValue += ei.pi->queenside_storm_value(WHITE)
+                    - ei.pi->kingside_storm_value(BLACK);
+
+    else if (   square_file(pos.king_square(WHITE)) <= FILE_D
+             && square_file(pos.king_square(BLACK)) >= FILE_E)
+
+        ei.mgValue += ei.pi->kingside_storm_value(WHITE)
+                    - ei.pi->queenside_storm_value(BLACK);
   }
 
   // Mobility
@@ -431,46 +414,40 @@ Value evaluate(const Position &pos, EvalInfo &ei, int threadID) {
 
   // If we don't already have an unusual scale factor, check for opposite
   // colored bishop endgames, and use a lower scale for those:
-  if(phase < PHASE_MIDGAME && pos.opposite_colored_bishops()
-     && ((factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0)) ||
-         (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0)))) {
-    if(pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) ==
-       2*BishopValueMidgame) {
-      // Only the two bishops
-      if(pos.pawn_count(WHITE) + pos.pawn_count(BLACK) == 1) {
-        // KBP vs KB with only a single pawn; almost certainly a draw.
-        if(factor[WHITE] == SCALE_FACTOR_NORMAL)
-          factor[WHITE] = ScaleFactor(8);
-        if(factor[BLACK] == SCALE_FACTOR_NORMAL)
-          factor[BLACK] = ScaleFactor(8);
-      }
-      else {
-        // At least two pawns
-        if(factor[WHITE] == SCALE_FACTOR_NORMAL)
-          factor[WHITE] = ScaleFactor(32);
-        if(factor[BLACK] == SCALE_FACTOR_NORMAL)
-          factor[BLACK] = ScaleFactor(32);
+  if (   phase < PHASE_MIDGAME
+      && pos.opposite_colored_bishops()
+      && (   (factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0))
+          || (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0))))
+  {
+      ScaleFactor sf;
+
+      // Only the two bishops ?
+      if (   pos.non_pawn_material(WHITE) == BishopValueMidgame
+          && pos.non_pawn_material(BLACK) == BishopValueMidgame)
+      {
+          // Check for KBP vs KB with only a single pawn that is almost
+          // certainly a draw or at least two pawns.
+          bool one_pawn = (pos.pawn_count(WHITE) + pos.pawn_count(BLACK) == 1);
+          sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
       }
-    }
-    else {
-      // Endgame with opposite-colored bishops, but also other pieces.
-      // Still a bit drawish, but not as drawish as with only the two
-      // bishops.
-      if(factor[WHITE] == SCALE_FACTOR_NORMAL)
-        factor[WHITE] = ScaleFactor(50);
-      if(factor[BLACK] == SCALE_FACTOR_NORMAL)
-        factor[BLACK] = ScaleFactor(50);
-    }
+      else
+          // Endgame with opposite-colored bishops, but also other pieces. Still
+          // a bit drawish, but not as drawish as with only the two bishops.
+           sf = ScaleFactor(50);
+
+      if (factor[WHITE] == SCALE_FACTOR_NORMAL)
+          factor[WHITE] = sf;
+      if (factor[BLACK] == SCALE_FACTOR_NORMAL)
+          factor[BLACK] = sf;
   }
 
   // Interpolate between the middle game and the endgame score, and
-  // return:
-  Value value = scale_by_game_phase(ei.mgValue, ei.egValue, phase, factor);
+  // return
+  Color stm = pos.side_to_move();
 
-  if(ei.mateThreat[stm] != MOVE_NONE)
-    return 8 * QueenValueMidgame - Sign[stm] * value;
-  else
-    return Sign[stm] * value;
+  Value v = Sign[stm] * scale_by_game_phase(ei.mgValue, ei.egValue, phase, factor);
+
+  return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
 }
 
 
@@ -479,24 +456,20 @@ Value evaluate(const Position &pos, EvalInfo &ei, int threadID) {
 /// we should add scores from the pawn and material hash tables?
 
 Value quick_evaluate(const Position &pos) {
-  Color stm;
-  Value mgValue, egValue;
-  ScaleFactor factor[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL};
-  Phase phase;
-  
-  assert(pos.is_ok());
 
-  stm = pos.side_to_move();
+  assert(pos.is_ok());
 
-  mgValue = pos.mg_value();
-  egValue = pos.eg_value();
-  phase = pos.game_phase();
+  static const
+  ScaleFactor sf[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL};  
 
-  Value value = scale_by_game_phase(mgValue, egValue, phase, factor);
+  Value mgv = pos.mg_value();
+  Value egv = pos.eg_value();
+  Phase ph = pos.game_phase();
+  Color stm = pos.side_to_move();
 
-  return Sign[stm] * value;
+  return Sign[stm] * scale_by_game_phase(mgv, egv, ph, sf);
 }
-  
+
 
 /// init_eval() initializes various tables used by the evaluation function.
 
@@ -528,9 +501,11 @@ void init_eval(int threads) {
 /// quit_eval() releases heap-allocated memory at program termination.
 
 void quit_eval() {
-  for(int i = 0; i < THREAD_MAX; i++) {
-    delete PawnTable[i];
-    delete MaterialTable[i];
+
+  for (int i = 0; i < THREAD_MAX; i++)
+  {
+      delete PawnTable[i];
+      delete MaterialTable[i];
   }
 }
 
@@ -538,32 +513,19 @@ void quit_eval() {
 /// read_weights() reads evaluation weights from the corresponding UCI
 /// parameters.
 
-void read_weights(Color sideToMove) {
-  WeightMobilityMidgame =
-    compute_weight(get_option_value_int("Mobility (Middle Game)"),
-                   WeightMobilityMidgameInternal);
-  WeightMobilityEndgame =
-    compute_weight(get_option_value_int("Mobility (Endgame)"),
-                   WeightMobilityEndgameInternal);
-  WeightPawnStructureMidgame =
-    compute_weight(get_option_value_int("Pawn Structure (Middle Game)"),
-                   WeightPawnStructureMidgameInternal);
-  WeightPawnStructureEndgame =
-    compute_weight(get_option_value_int("Pawn Structure (Endgame)"),
-                   WeightPawnStructureEndgameInternal);
-  WeightPassedPawnsMidgame =
-    compute_weight(get_option_value_int("Passed Pawns (Middle Game)"),
-                   WeightPassedPawnsMidgameInternal);
-  WeightPassedPawnsEndgame =
-    compute_weight(get_option_value_int("Passed Pawns (Endgame)"),
-                   WeightPassedPawnsEndgameInternal);
-  WeightKingSafety[sideToMove] =
-    compute_weight(get_option_value_int("Cowardice"), WeightKingSafetyInternal);
-  WeightKingSafety[opposite_color(sideToMove)] =
-    compute_weight(get_option_value_int("Aggressiveness"),
-                   WeightKingSafetyInternal);
-  WeightKingSafety[opposite_color(sideToMove)] =
-    (get_option_value_int("Aggressiveness") * 0x100) / 100;
+void read_weights(Color us) {
+
+  WeightMobilityMidgame      = weight_option("Mobility (Middle Game)", WeightMobilityMidgameInternal);
+  WeightMobilityEndgame      = weight_option("Mobility (Endgame)", WeightMobilityEndgameInternal);
+  WeightPawnStructureMidgame = weight_option("Pawn Structure (Middle Game)", WeightPawnStructureMidgameInternal);
+  WeightPawnStructureEndgame = weight_option("Pawn Structure (Endgame)", WeightPawnStructureEndgameInternal);
+  WeightPassedPawnsMidgame   = weight_option("Passed Pawns (Middle Game)", WeightPassedPawnsMidgameInternal);
+  WeightPassedPawnsEndgame   = weight_option("Passed Pawns (Endgame)", WeightPassedPawnsEndgameInternal);
+
+  Color them = opposite_color(us);
+
+  WeightKingSafety[us]   = weight_option("Cowardice", WeightKingSafetyInternal);
+  WeightKingSafety[them] = weight_option("Aggressiveness", WeightKingOppSafetyInternal);
 
   init_safety();
 }
@@ -571,239 +533,213 @@ void read_weights(Color sideToMove) {
 
 namespace {
 
-  // evaluate_knight() assigns bonuses and penalties to a knight of a given
-  // color on a given square.
-  
-  void evaluate_knight(const Position &p, Square s, Color us, EvalInfo &ei) {
+  // evaluate_common() computes terms common to all pieces attack
+
+  int evaluate_common(const Position&p, const Bitboard& b, Color us, EvalInfo& ei,
+                       int AttackWeight, const Value* mgBonus, const Value* egBonus,
+                       Square s = SQ_NONE, const Value* OutpostBonus = NULL) {
 
     Color them = opposite_color(us);
-    Bitboard b = p.knight_attacks(s);
-    ei.attackedBy[us][KNIGHT] |= b;
 
     // King attack
-    if(b & ei.attackZone[us]) {
-      ei.attackCount[us]++;
-      ei.attackWeight[us] += KnightAttackWeight;
-      Bitboard bb = (b & ei.attackedBy[them][KING]);
-      if(bb) ei.attacked[us] += count_1s_max_15(bb);
+    if (b & ei.kingZone[us])
+    {
+        ei.kingAttackersCount[us]++;
+        ei.kingAttackersWeight[us] += AttackWeight;
+        Bitboard bb = (b & ei.attackedBy[them][KING]);
+        if (bb)
+            ei.kingAdjacentZoneAttacksCount[us] += count_1s_max_15(bb);
     }
-        
+
     // Mobility
     int mob = count_1s_max_15(b & ~p.pieces_of_color(us));
-    ei.mgMobility += Sign[us] * MidgameKnightMobilityBonus[mob];
-    ei.egMobility += Sign[us] * EndgameKnightMobilityBonus[mob];
-
-    // Knight outposts:
-    if(p.square_is_weak(s, them)) {
-      Value v, bonus;
-      
-      // Initial bonus based on square:
-      v = bonus = KnightOutpostBonus[relative_square(us, s)];
-
-      // Increase bonus if supported by pawn, especially if the opponent has
-      // no minor piece which can exchange the outpost piece:
-      if(v && p.pawn_attacks(them, s) & p.pawns(us)) {
-        bonus += v/2;
-        if(p.knight_count(them) == 0 &&
-           (SquaresByColorBB[square_color(s)] &
-            p.bishops(them)) == EmptyBoardBB) {
-          bonus += v;
-        }
-      }
+    ei.mgMobility += Sign[us] * mgBonus[mob];
+    ei.egMobility += Sign[us] * egBonus[mob];
+
+    // Bishop and Knight outposts
+    if (!OutpostBonus || !p.square_is_weak(s, them))
+        return mob;
 
-      ei.mgValue += Sign[us] * bonus;
-      ei.egValue += Sign[us] * bonus;
+    // Initial bonus based on square
+    Value v, bonus;
+    v = bonus = OutpostBonus[relative_square(us, s)];
+
+    // Increase bonus if supported by pawn, especially if the opponent has
+    // no minor piece which can exchange the outpost piece
+    if (v && (p.pawn_attacks(them, s) & p.pawns(us)))
+    {
+        bonus += v / 2;
+        if (   p.knight_count(them) == 0
+            && (SquaresByColorBB[square_color(s)] & p.bishops(them)) == EmptyBoardBB)
+            bonus += v;
     }
+    ei.mgValue += Sign[us] * bonus;
+    ei.egValue += Sign[us] * bonus;
+    return mob;
+  }
+
+
+  // evaluate_knight() assigns bonuses and penalties to a knight of a given
+  // color on a given square.
+
+  void evaluate_knight(const Position &p, Square s, Color us, EvalInfo &ei) {
+
+    Bitboard b = p.piece_attacks<KNIGHT>(s);
+    ei.attackedBy[us][KNIGHT] |= b;
+
+    // King attack, mobility and outposts
+    evaluate_common(p, b, us, ei, KnightAttackWeight, MidgameKnightMobilityBonus,
+                    EndgameKnightMobilityBonus, s, KnightOutpostBonus);
   }
 
 
   // evaluate_bishop() assigns bonuses and penalties to a bishop of a given
   // color on a given square.
-  
+
   void evaluate_bishop(const Position &p, Square s, Color us, EvalInfo &ei) {
 
-    Color them = opposite_color(us);
-    Bitboard b =
-      bishop_attacks_bb(s, p.occupied_squares() & ~p.queens(us));
-                                   
+    Bitboard b = bishop_attacks_bb(s, p.occupied_squares() & ~p.queens(us));
     ei.attackedBy[us][BISHOP] |= b;
 
-    // King attack
-    if(b & ei.attackZone[us]) {
-      ei.attackCount[us]++;
-      ei.attackWeight[us] += BishopAttackWeight;
-      Bitboard bb = (b & ei.attackedBy[them][KING]);
-      if(bb) ei.attacked[us] += count_1s_max_15(bb);
-    }
-
-    // Mobility:
-    int mob = count_1s_max_15(b & ~p.pieces_of_color(us));
-    ei.mgMobility += Sign[us] * MidgameBishopMobilityBonus[mob];
-    ei.egMobility += Sign[us] * EndgameBishopMobilityBonus[mob];
-
-    // Bishop outposts:
-    if(p.square_is_weak(s, them)) {
-      Value v, bonus;
-      
-      // Initial bonus based on square:
-      v = bonus = BishopOutpostBonus[relative_square(us, s)];
-
-      // Increase bonus if supported by pawn, especially if the opponent has
-      // no minor piece which can exchange the outpost piece:
-      if(v && p.pawn_attacks(them, s) & p.pawns(us)) {
-        bonus += v/2;
-        if(p.knight_count(them) == 0 &&
-           (SquaresByColorBB[square_color(s)] &
-            p.bishops(them)) == EmptyBoardBB) {
-          bonus += v;
-        }
-      }
-
-      ei.mgValue += Sign[us] * bonus;
-      ei.egValue += Sign[us] * bonus;
-    }    
+    // King attack, mobility and outposts
+    evaluate_common(p, b, us, ei, BishopAttackWeight, MidgameBishopMobilityBonus,
+                    EndgameBishopMobilityBonus, s, BishopOutpostBonus);
   }
-  
+
 
   // evaluate_rook() assigns bonuses and penalties to a rook of a given
   // color on a given square.
-  
-  void evaluate_rook(const Position &p, Square s, Color us, EvalInfo &ei) {
 
-    Color them = opposite_color(us);
-    
-    // Open and half-open files:
-    File f = square_file(s);
-    if(ei.pi->file_is_half_open(us, f)) {
-      if(ei.pi->file_is_half_open(them, f)) {
-        ei.mgValue += Sign[us] * RookOpenFileBonus;
-        ei.egValue += Sign[us] * RookOpenFileBonus;
-      }
-      else {
-        ei.mgValue += Sign[us] * RookHalfOpenFileBonus;
-        ei.egValue += Sign[us] * RookHalfOpenFileBonus;
-      }
-    }
-
-    // Rook on 7th rank:
-    if(pawn_rank(us, s) == RANK_7 &&
-       pawn_rank(us, p.king_square(them)) == RANK_8) {
-      ei.mgValue += Sign[us] * MidgameRookOn7thBonus;
-      ei.egValue += Sign[us] * EndgameRookOn7thBonus;
-    }
+  void evaluate_rook(const Position &p, Square s, Color us, EvalInfo &ei) {
 
     //Bitboard b = p.rook_attacks(s);
-    Bitboard b =
-      rook_attacks_bb(s, p.occupied_squares() & ~p.rooks_and_queens(us));
+    Bitboard b = rook_attacks_bb(s, p.occupied_squares() & ~p.rooks_and_queens(us));
     ei.attackedBy[us][ROOK] |= b;
 
-    // King attack
-    if(b & ei.attackZone[us]) {
-      ei.attackCount[us]++;
-      ei.attackWeight[us] += RookAttackWeight;
-      Bitboard bb = (b & ei.attackedBy[them][KING]);
-      if(bb) ei.attacked[us] += count_1s_max_15(bb);
+    // King attack and mobility
+    int mob = evaluate_common(p, b, us, ei, RookAttackWeight, MidgameRookMobilityBonus,
+                              EndgameRookMobilityBonus);
+
+    // Rook on 7th rank
+    Color them = opposite_color(us);
+
+    if (   relative_rank(us, s) == RANK_7
+        && relative_rank(us, p.king_square(them)) == RANK_8)
+    {
+        ei.mgValue += Sign[us] * MidgameRookOn7thBonus;
+        ei.egValue += Sign[us] * EndgameRookOn7thBonus;
     }
 
-    // Mobility
-    int mob = count_1s_max_15(b & ~p.pieces_of_color(us));
-    ei.mgMobility += Sign[us] * MidgameRookMobilityBonus[mob];
-    ei.egMobility += Sign[us] * EndgameRookMobilityBonus[mob];
-
-    // Penalize rooks which are trapped inside a king which has lost the
-    // right to castle:
-    if(mob <= 6 && !ei.pi->file_is_half_open(us, f)) {
-      Square ksq = p.king_square(us);
-      if(square_file(ksq) >= FILE_E && square_file(s) > square_file(ksq) &&
-         (pawn_rank(us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s))) {
-        // Is there a half-open file between the king and the edge of the
-        // board?
-        if(!(ei.pi->has_open_file_to_right(us, square_file(ksq)))) {
-          ei.mgValue -= p.can_castle(us)?
-            Sign[us] * ((TrappedRookPenalty - mob * 16) / 2) :
-            Sign[us] * (TrappedRookPenalty - mob * 16);
+    // Open and half-open files
+    File f = square_file(s);
+    if (ei.pi->file_is_half_open(us, f))
+    {
+        if (ei.pi->file_is_half_open(them, f))
+        {
+            ei.mgValue += Sign[us] * RookOpenFileBonus;
+            ei.egValue += Sign[us] * RookOpenFileBonus;
         }
-      }
-      else if(square_file(ksq) <= FILE_D && square_file(s) < square_file(ksq)
-              && (pawn_rank(us, ksq) == RANK_1 ||
-                  square_rank(ksq) == square_rank(s))) {
-        // Is there a half-open file between the king and the edge of the
-        // board?
-        if(!(ei.pi->has_open_file_to_left(us, square_file(ksq)))) {
-          ei.mgValue -= p.can_castle(us)?
-            Sign[us] * ((TrappedRookPenalty - mob * 16) / 2) :
-            Sign[us] * (TrappedRookPenalty - mob * 16);
+        else
+        {
+            ei.mgValue += Sign[us] * RookHalfOpenFileBonus;
+            ei.egValue += Sign[us] * RookHalfOpenFileBonus;
         }
-      }
+    }
+
+    // Penalize rooks which are trapped inside a king. Penalize more if
+    // king has lost right to castle
+    if (mob > 6 || ei.pi->file_is_half_open(us, f))
+        return;
+
+    Square ksq = p.king_square(us);
+
+    if (    square_file(ksq) >= FILE_E
+        &&  square_file(s) > square_file(ksq)
+        && (relative_rank(us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
+    {
+        // Is there a half-open file between the king and the edge of the board?
+        if (!ei.pi->has_open_file_to_right(us, square_file(ksq)))
+            ei.mgValue -= p.can_castle(us)? Sign[us] * ((TrappedRookPenalty - mob * 16) / 2)
+                                          : Sign[us] *  (TrappedRookPenalty - mob * 16);
+    }
+    else if (    square_file(ksq) <= FILE_D
+             &&  square_file(s) < square_file(ksq)
+             && (relative_rank(us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
+    {
+        // Is there a half-open file between the king and the edge of the board?
+        if (!ei.pi->has_open_file_to_left(us, square_file(ksq)))
+            ei.mgValue -= p.can_castle(us)? Sign[us] * ((TrappedRookPenalty - mob * 16) / 2)
+                                          : Sign[us] * (TrappedRookPenalty - mob * 16);
     }
   }
 
 
   // evaluate_queen() assigns bonuses and penalties to a queen of a given
   // color on a given square.
-  
+
   void evaluate_queen(const Position &p, Square s, Color us, EvalInfo &ei) {
 
-    Color them = opposite_color(us);
+    Bitboard b = p.piece_attacks<QUEEN>(s);
+    ei.attackedBy[us][QUEEN] |= b;
 
-    // Queen on 7th rank:
-    if(pawn_rank(us, s) == RANK_7 &&
-       pawn_rank(us, p.king_square(them)) == RANK_8) {
-      ei.mgValue += Sign[us] * MidgameQueenOn7thBonus;
-      ei.egValue += Sign[us] * EndgameQueenOn7thBonus;
-    }
+    // King attack and mobility
+    evaluate_common(p, b, us, ei, QueenAttackWeight, MidgameQueenMobilityBonus,
+                    EndgameQueenMobilityBonus);
 
-    Bitboard b = p.queen_attacks(s);
-    ei.attackedBy[us][QUEEN] |= b;
+    // Queen on 7th rank
+    Color them = opposite_color(us);
 
-    // King attack
-    if(b & ei.attackZone[us]) {
-      ei.attackCount[us]++;
-      ei.attackWeight[us] += QueenAttackWeight;
-      Bitboard bb = (b & ei.attackedBy[them][KING]);
-      if(bb) ei.attacked[us] += count_1s_max_15(bb);
+    if (   relative_rank(us, s) == RANK_7
+        && relative_rank(us, p.king_square(them)) == RANK_8)
+    {
+        ei.mgValue += Sign[us] * MidgameQueenOn7thBonus;
+        ei.egValue += Sign[us] * EndgameQueenOn7thBonus;
     }
-    
-    // Mobility
-    int mob = count_1s(b & ~p.pieces_of_color(us));
-    ei.mgMobility += Sign[us] * MidgameQueenMobilityBonus[mob];
-    ei.egMobility += Sign[us] * EndgameQueenMobilityBonus[mob];
   }
 
+  inline Bitboard shiftRowsDown(const Bitboard& b, int num) {
+
+    return b >> (num << 3);
+  }
 
   // evaluate_king() assigns bonuses and penalties to a king of a given
   // color on a given square.
-  
+
   void evaluate_king(const Position &p, Square s, Color us, EvalInfo &ei) {
-    
+
     int shelter = 0, sign = Sign[us];
 
-    // King shelter.
-    if(pawn_rank(us, s) <= RANK_4) {
-      Bitboard pawns = p.pawns(us) & this_and_neighboring_files_bb(s);
-      Rank r = square_rank(s);
-      for(int i = 0; i < 3; i++)
-        shelter += count_1s_8bit(pawns >> ((r+(i+1)*sign) * 8)) * (64>>i);
-      ei.mgValue += sign * Value(shelter);
+    // King shelter
+    if (relative_rank(us, s) <= RANK_4)
+    {
+        Bitboard pawns = p.pawns(us) & this_and_neighboring_files_bb(s);
+        Rank r = square_rank(s);
+        for (int i = 1; i < 4; i++)
+            shelter += count_1s_8bit(shiftRowsDown(pawns, r+i*sign)) * (128>>i);
+
+        ei.mgValue += sign * Value(shelter);
     }
 
     // King safety.  This is quite complicated, and is almost certainly far
-    // from optimally tuned.  
+    // from optimally tuned.
     Color them = opposite_color(us);
-    if(p.queen_count(them) >= 1 && ei.attackCount[them] >= 2
-       && p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame
-       && ei.attacked[them]) {
 
+    if (   p.queen_count(them) >= 1
+        && ei.kingAttackersCount[them] >= 2
+        && p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame
+        && ei.kingAdjacentZoneAttacksCount[them])
+    {
       // Is it the attackers turn to move?
       bool sente = (them == p.side_to_move());
-      
+
       // Find the attacked squares around the king which has no defenders
-      // apart from the king itself:
+      // apart from the king itself
       Bitboard undefended =
-        ei.attacked_by(them) & ~ei.attacked_by(us, PAWN)
-        & ~ei.attacked_by(us, KNIGHT) & ~ei.attacked_by(us, BISHOP)
-        & ~ei.attacked_by(us, ROOK) & ~ei.attacked_by(us, QUEEN)
-        & ei.attacked_by(us, KING);
+             ei.attacked_by(them)       & ~ei.attacked_by(us, PAWN)
+          & ~ei.attacked_by(us, KNIGHT) & ~ei.attacked_by(us, BISHOP)
+          & ~ei.attacked_by(us, ROOK)   & ~ei.attacked_by(us, QUEEN)
+          & ei.attacked_by(us, KING);
+
       Bitboard occ = p.occupied_squares(), b, b2;
 
       // Initialize the 'attackUnits' variable, which is used later on as an
@@ -812,113 +748,134 @@ namespace {
       // undefended squares around the king, the square of the king, and the
       // quality of the pawn shelter.
       int attackUnits =
-        Min((ei.attackCount[them] * ei.attackWeight[them]) / 2, 25)
-        + (ei.attacked[them] + count_1s_max_15(undefended)) * 3
-        + InitKingDanger[relative_square(us, s)] - shelter / 32;
+            Min((ei.kingAttackersCount[them] * ei.kingAttackersWeight[them]) / 2, 25)
+          + (ei.kingAdjacentZoneAttacksCount[them] + count_1s_max_15(undefended)) * 3
+          + InitKingDanger[relative_square(us, s)] - shelter / 32;
 
-      // Analyse safe queen contact checks:
+      // Analyse safe queen contact checks
       b = undefended & ei.attacked_by(them, QUEEN) & ~p.pieces_of_color(them);
-      if(b) {
+      if (b)
+      {
         Bitboard attackedByOthers =
-          ei.attacked_by(them, PAWN) | ei.attacked_by(them, KNIGHT)
-          | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, ROOK);
+              ei.attacked_by(them, PAWN)   | ei.attacked_by(them, KNIGHT)
+            | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, ROOK);
+
         b &= attackedByOthers;
-        if(b) {
+        if (b)
+        {
           // The bitboard b now contains the squares available for safe queen
           // contact checks.
           int count = count_1s_max_15(b);
-          attackUnits += QueenContactCheckBonus * count * (sente? 2 : 1);
+          attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
 
           // Is there a mate threat?
-          if(QueenContactMates && !p.is_check()) {
+          if (QueenContactMates && !p.is_check())
+          {
             Bitboard escapeSquares =
-              p.king_attacks(s) & ~p.pieces_of_color(us) & ~attackedByOthers;
-            while(b) {
-              Square from, to = pop_1st_bit(&b);
-              if(!(escapeSquares
-                   & ~queen_attacks_bb(to, occ & clear_mask_bb(s)))) {
-                // We have a mate, unless the queen is pinned or there
-                // is an X-ray attack through the queen.
-                for(int i = 0; i < p.queen_count(them); i++) {
-                  from = p.queen_list(them, i);
-                  if(bit_is_set(p.queen_attacks(from), to)
-                     && !bit_is_set(p.pinned_pieces(them), from)
-                     && !(rook_attacks_bb(to, occ & clear_mask_bb(from))
-                          & p.rooks_and_queens(us))
-                     && !(rook_attacks_bb(to, occ & clear_mask_bb(from))
-                          & p.rooks_and_queens(us)))
-                    ei.mateThreat[them] = make_move(from, to);
+                p.piece_attacks<KING>(s) & ~p.pieces_of_color(us) & ~attackedByOthers;
+
+            while (b)
+            {
+                Square from, to = pop_1st_bit(&b);
+                if (!(escapeSquares & ~queen_attacks_bb(to, occ & clear_mask_bb(s))))
+                {
+                    // We have a mate, unless the queen is pinned or there
+                    // is an X-ray attack through the queen.
+                    for (int i = 0; i < p.queen_count(them); i++)
+                    {
+                        from = p.queen_list(them, i);
+                        if (    bit_is_set(p.piece_attacks<QUEEN>(from), to)
+                            && !bit_is_set(p.pinned_pieces(them), from)
+                            && !(rook_attacks_bb(to, occ & clear_mask_bb(from)) & p.rooks_and_queens(us))
+                            && !(rook_attacks_bb(to, occ & clear_mask_bb(from)) & p.rooks_and_queens(us)))
+                            
+                            ei.mateThreat[them] = make_move(from, to);
+                    }
                 }
-              }
             }
           }
         }
       }
-
       // Analyse safe rook contact checks:
-      if(RookContactCheckBonus) {
-        b = undefended & ei.attacked_by(them, ROOK) & ~p.pieces_of_color(them);
-        if(b) {
-          Bitboard attackedByOthers =
-            ei.attacked_by(them, PAWN) | ei.attacked_by(them, KNIGHT)
-            | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, QUEEN);
-          b &= attackedByOthers;
-          if(b) {
-            int count = count_1s_max_15(b);
-            attackUnits += (RookContactCheckBonus * count * (sente? 2 : 1));
+      if (RookContactCheckBonus)
+      {
+          b = undefended & ei.attacked_by(them, ROOK) & ~p.pieces_of_color(them);
+          if (b)
+          {
+              Bitboard attackedByOthers =
+                    ei.attacked_by(them, PAWN)   | ei.attacked_by(them, KNIGHT)
+                  | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, QUEEN);
+
+              b &= attackedByOthers;
+              if (b)
+              {
+                  int count = count_1s_max_15(b);
+                  attackUnits += (RookContactCheckBonus * count * (sente? 2 : 1));
+              }
           }
-        }
       }
-      
       // Analyse safe distance checks:
-      if(QueenCheckBonus > 0 || RookCheckBonus > 0) {
-        b = p.rook_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
-
-        // Queen checks
-        b2 = b & ei.attacked_by(them, QUEEN);
-        if(b2) attackUnits += QueenCheckBonus * count_1s_max_15(b2);
-
-        // Rook checks
-        b2 = b & ei.attacked_by(them, ROOK);
-        if(b2) attackUnits += RookCheckBonus * count_1s_max_15(b2);
+      if (QueenCheckBonus > 0 || RookCheckBonus > 0)
+      {
+          b = p.piece_attacks<ROOK>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
+
+          // Queen checks
+          b2 = b & ei.attacked_by(them, QUEEN);
+          if( b2)
+              attackUnits += QueenCheckBonus * count_1s_max_15(b2);
+
+          // Rook checks
+          b2 = b & ei.attacked_by(them, ROOK);
+          if (b2)
+              attackUnits += RookCheckBonus * count_1s_max_15(b2);
       }
-      if(QueenCheckBonus > 0 || BishopCheckBonus > 0) {
-        b = p.bishop_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
-        // Queen checks
-        b2 = b & ei.attacked_by(them, QUEEN);
-        if(b2) attackUnits += QueenCheckBonus * count_1s_max_15(b2);
-
-        // Bishop checks
-        b2 = b & ei.attacked_by(them, BISHOP);
-        if(b2) attackUnits += BishopCheckBonus * count_1s_max_15(b2);
+      if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
+      {
+          b = p.piece_attacks<BISHOP>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
+
+          // Queen checks
+          b2 = b & ei.attacked_by(them, QUEEN);
+          if (b2)
+              attackUnits += QueenCheckBonus * count_1s_max_15(b2);
+
+          // Bishop checks
+          b2 = b & ei.attacked_by(them, BISHOP);
+          if (b2)
+              attackUnits += BishopCheckBonus * count_1s_max_15(b2);
       }
-      if(KnightCheckBonus > 0) {
-        b = p.knight_attacks(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
-        // Knight checks
-        b2 = b & ei.attacked_by(them, KNIGHT);
-        if(b2) attackUnits += KnightCheckBonus * count_1s_max_15(b2);
+      if (KnightCheckBonus > 0)
+      {
+          b = p.piece_attacks<KNIGHT>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
+
+          // Knight checks
+          b2 = b & ei.attacked_by(them, KNIGHT);
+          if (b2)
+              attackUnits += KnightCheckBonus * count_1s_max_15(b2);
       }
 
       // Analyse discovered checks (only for non-pawns right now, consider
       // adding pawns later).
-      if(DiscoveredCheckBonus) {
+      if (DiscoveredCheckBonus)
+      {
         b = p.discovered_check_candidates(them) & ~p.pawns();
-        if(b)
-          attackUnits +=
-            DiscoveredCheckBonus * count_1s_max_15(b) * (sente? 2 : 1);
+        if (b)
+          attackUnits += DiscoveredCheckBonus * count_1s_max_15(b) * (sente? 2 : 1);
       }
 
       // Has a mate threat been found?  We don't do anything here if the
       // side with the mating move is the side to move, because in that
       // case the mating side will get a huge bonus at the end of the main
       // evaluation function instead.
-      if(ei.mateThreat[them] != MOVE_NONE)
-        attackUnits += MateThreatBonus;
+      if (ei.mateThreat[them] != MOVE_NONE)
+          attackUnits += MateThreatBonus;
 
       // Ensure that attackUnits is between 0 and 99, in order to avoid array
       // out of bounds errors:
-      if(attackUnits < 0) attackUnits = 0;
-      if(attackUnits >= 100) attackUnits = 99;
+      if (attackUnits < 0)
+          attackUnits = 0;
+
+      if (attackUnits >= 100)
+          attackUnits = 99;
 
       // Finally, extract the king safety score from the SafetyTable[] array.
       // Add the score to the evaluation, and also to ei.futilityMargin.  The
@@ -927,9 +884,11 @@ namespace {
       // capturing a single attacking piece can therefore result in a score
       // change far bigger than the value of the captured piece.
       Value v = apply_weight(SafetyTable[attackUnits], WeightKingSafety[us]);
+
       ei.mgValue -= sign * v;
-      if(us == p.side_to_move())
-        ei.futilityMargin += v;
+
+      if (us == p.side_to_move())
+          ei.futilityMargin += v;
     }
   }
 
@@ -951,7 +910,7 @@ namespace {
         assert(pos.piece_on(s) == pawn_of_color(us));
         assert(pos.pawn_is_passed(us, s));
 
-        int r = int(pawn_rank(us, s) - RANK_2);
+        int r = int(relative_rank(us, s) - RANK_2);
         int tr = Max(0, r * (r-1));
         Square blockSq = s + pawn_push(us);
 
@@ -1016,7 +975,7 @@ namespace {
             + ((us == pos.side_to_move())? 0 : 1);
 
           if(d < 0) {
-            int mtg = RANK_8 - pawn_rank(us, s);
+            int mtg = RANK_8 - relative_rank(us, s);
             int blockerCount =
               count_1s_max_15(squares_in_front_of(us,s)&pos.occupied_squares());
             mtg += blockerCount;
@@ -1079,29 +1038,23 @@ namespace {
   // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
   // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
   // if it is.
-  
+
   void evaluate_trapped_bishop_a7h7(const Position &pos, Square s, Color us,
                                     EvalInfo &ei) {
-    Piece pawn = pawn_of_color(opposite_color(us));
-    Square b6, b8;
 
     assert(square_is_ok(s));
     assert(pos.piece_on(s) == bishop_of_color(us));
 
-    if(square_file(s) == FILE_A) {
-      b6 = relative_square(us, SQ_B6);
-      b8 = relative_square(us, SQ_B8);
-    }
-    else {
-      b6 = relative_square(us, SQ_G6);
-      b8 = relative_square(us, SQ_G8);
-    }
+    Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
+    Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
 
-    if(pos.piece_on(b6) == pawn && pos.see(s, b6) < 0 && pos.see(s, b8) < 0) {
-      ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty;
-      ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty;
+    if (   pos.piece_on(b6) == pawn_of_color(opposite_color(us))
+        && pos.see(s, b6) < 0
+        && pos.see(s, b8) < 0)
+    {
+        ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty;
+        ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty;
     }
-
   }
 
 
@@ -1109,7 +1062,7 @@ namespace {
   // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
   // black), and assigns a penalty if it is.  This pattern can obviously
   // only occur in Chess960 games.
-  
+
   void evaluate_trapped_bishop_a1h1(const Position &pos, Square s, Color us,
                                     EvalInfo &ei) {
     Piece pawn = pawn_of_color(us);
@@ -1139,7 +1092,7 @@ namespace {
         penalty = TrappedBishopA1H1Penalty;
       else
         penalty = TrappedBishopA1H1Penalty / 2;
-      
+
       ei.mgValue -= Sign[us] * penalty;
       ei.egValue -= Sign[us] * penalty;
     }
@@ -1157,23 +1110,22 @@ namespace {
   // scale_by_game_phase interpolates between a middle game and an endgame
   // score, based on game phase.  It also scales the return value by a
   // ScaleFactor array.
-  
-  Value scale_by_game_phase(Value mv, Value ev, Phase ph, ScaleFactor sf[]) {
+
+  Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]) {
+
     assert(mv > -VALUE_INFINITE && mv < VALUE_INFINITE);
     assert(ev > -VALUE_INFINITE && ev < VALUE_INFINITE);
     assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
 
-    if(ev > Value(0))
-      ev = apply_scale_factor(ev, sf[WHITE]);
-    else
-      ev = apply_scale_factor(ev, sf[BLACK]);
+    ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]);
 
-    // Superlinear interpolator
-    int sli_ph = int(ph);
-    sli_ph -= (64 - sli_ph) / 4;
-    sli_ph = Min(PHASE_MIDGAME, Max(PHASE_ENDGAME, sli_ph)); // ceiling
+    // Linearized sigmoid interpolator
+    int sph = int(ph);
+    sph -= (64 - sph) / 4;
+    sph = Min(PHASE_MIDGAME, Max(PHASE_ENDGAME, sph));
+
+    Value result = Value(int((mv * sph + ev * (128 - sph)) / 128));
 
-    Value result = Value(int((mv * sli_ph + ev * (128 - sli_ph)) / 128));
     return Value(int(result) & ~(GrainSize - 1));
   }
 
@@ -1181,7 +1133,7 @@ namespace {
   // count_1s_8bit() counts the number of nonzero bits in the 8 least
   // significant bits of a Bitboard. This function is used by the king
   // shield evaluation.
-  
+
   int count_1s_8bit(Bitboard b) {
     return int(BitCount8Bit[b & 0xFF]);
   }
@@ -1194,45 +1146,55 @@ namespace {
     uciWeight = (uciWeight * 0x100) / 100;
     return (uciWeight * internalWeight) / 0x100;
   }
-  
+
+
+  // helper used in read_weights()
+  int weight_option(const std::string& opt, int weight) {
+
+    return compute_weight(get_option_value_int(opt), weight);
+  }
+
 
   // init_safety() initizes the king safety evaluation, based on UCI
   // parameters.  It is called from read_weights().
-  
+
   void init_safety() {
-    double a, b;
-    int maxSlope, peak, i, j;
-    
+
     QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
-    RookContactCheckBonus = get_option_value_int("Rook Contact Check Bonus");
-    QueenCheckBonus = get_option_value_int("Queen Check Bonus");
-    RookCheckBonus = get_option_value_int("Rook Check Bonus");
-    BishopCheckBonus = get_option_value_int("Bishop Check Bonus");
-    KnightCheckBonus = get_option_value_int("Knight Check Bonus");
-    DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus");
-    MateThreatBonus = get_option_value_int("Mate Threat Bonus");
-
-    a = get_option_value_int("King Safety Coefficient") / 100.0;
-    b = get_option_value_int("King Safety X Intercept") * 1.0;
-    maxSlope = get_option_value_int("King Safety Max Slope");
-    peak = (get_option_value_int("King Safety Max Value") * 256) / 100;
-    
-    for(i = 0; i < 100; i++) {
-      if(i < b) SafetyTable[i] = Value(0);
-      else if(get_option_value_string("King Safety Curve") == "Quadratic")
-        SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
-      else if(get_option_value_string("King Safety Curve") == "Linear")
-        SafetyTable[i] = Value((int)(100 * a * (i - b)));
+    RookContactCheckBonus  = get_option_value_int("Rook Contact Check Bonus");
+    QueenCheckBonus        = get_option_value_int("Queen Check Bonus");
+    RookCheckBonus         = get_option_value_int("Rook Check Bonus");
+    BishopCheckBonus       = get_option_value_int("Bishop Check Bonus");
+    KnightCheckBonus       = get_option_value_int("Knight Check Bonus");
+    DiscoveredCheckBonus   = get_option_value_int("Discovered Check Bonus");
+    MateThreatBonus        = get_option_value_int("Mate Threat Bonus");
+
+    int maxSlope = get_option_value_int("King Safety Max Slope");
+    int peak     = get_option_value_int("King Safety Max Value") * 256 / 100;
+    double a     = get_option_value_int("King Safety Coefficient") / 100.0;
+    double b     = get_option_value_int("King Safety X Intercept");
+    bool quad    = (get_option_value_string("King Safety Curve") == "Quadratic");
+    bool linear  = (get_option_value_string("King Safety Curve") == "Linear");
+
+    for (int i = 0; i < 100; i++)
+    {
+        if (i < b)
+            SafetyTable[i] = Value(0);
+        else if(quad)
+            SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
+        else if(linear)
+            SafetyTable[i] = Value((int)(100 * a * (i - b)));
     }
 
-    for(i = 0; i < 100; i++)
-      if(SafetyTable[i+1] - SafetyTable[i] > maxSlope) {
-        for(j = i + 1; j < 100; j++)
-          SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
-      }
-    for(i = 0; i < 100; i++)
-      if(SafetyTable[i]  > Value(peak))
-        SafetyTable[i] = Value(peak);
+    for (int i = 0; i < 100; i++)
+    {
+        if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
+            for (int j = i + 1; j < 100; j++)
+                SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
+
+        if (SafetyTable[i]  > Value(peak))
+            SafetyTable[i] = Value(peak);
+    }
   }
-  
+
 }