Simplify away pinnedPieces bitboard in EvalInfo (#975)

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index a00dbf8afb952a8ebe89c4cb9903d56d6a98ebe8..6e33bb7215d0579e035915d20c40811dac8c8ae9 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -75,7 +75,6 @@ namespace {
 
     Material::Entry* me;
     Pawns::Entry* pe;
 
     Material::Entry* me;
     Pawns::Entry* pe;

-    Bitboard pinnedPieces[COLOR_NB];

     Bitboard mobilityArea[COLOR_NB];
 
     // attackedBy[color][piece type] is a bitboard representing all squares
     Bitboard mobilityArea[COLOR_NB];
 
     // attackedBy[color][piece type] is a bitboard representing all squares


@@ -135,19 +134,13 @@ namespace {
       S(118,174), S(119,177), S(123,191), S(128,199) }
   };
 
       S(118,174), S(119,177), S(123,191), S(128,199) }
   };
 

-  // Outpost[knight/bishop][supported by pawn] contains bonuses for knights and
-  // bishops outposts, bigger if outpost piece is supported by a pawn.
+  // Outpost[knight/bishop][supported by pawn] contains bonuses for minor
+  // pieces if they can reach an outpost square, bigger if that square is
+  // supported by a pawn. If the minor piece occupies an outpost square
+  // then score is doubled.

   const Score Outpost[][2] = {
   const Score Outpost[][2] = {

-    { S(43,11), S(65,20) }, // Knights
-    { S(20, 3), S(29, 8) }  // Bishops
-  };
-
-  // ReachableOutpost[knight/bishop][supported by pawn] contains bonuses for
-  // knights and bishops which can reach an outpost square in one move, bigger
-  // if outpost square is supported by a pawn.
-  const Score ReachableOutpost[][2] = {
-    { S(21, 5), S(35, 8) }, // Knights
-    { S( 8, 0), S(14, 4) }  // Bishops
+    { S(22, 6), S(33, 9) }, // Knight
+    { S( 9, 2), S(14, 4) }  // Bishop

   };
 
   // RookOnFile[semiopen/open] contains bonuses for each rook when there is no
   };
 
   // RookOnFile[semiopen/open] contains bonuses for each rook when there is no


@@ -223,7 +216,7 @@ namespace {
   const int KnightCheck       = 924;
 
   // Threshold for lazy evaluation
   const int KnightCheck       = 924;
 
   // Threshold for lazy evaluation

-  const Value LazyEval = Value(1500);
+  const Value LazyThreshold = Value(1500);

 
   // eval_init() initializes king and attack bitboards for a given color
   // adding pawn attacks. To be done at the beginning of the evaluation.
 
   // eval_init() initializes king and attack bitboards for a given color
   // adding pawn attacks. To be done at the beginning of the evaluation.


@@ -236,8 +229,6 @@ namespace {
     const Square Down = (Us == WHITE ? SOUTH : NORTH);
     const Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB);
 
     const Square Down = (Us == WHITE ? SOUTH : NORTH);
     const Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB);
 

-    ei.pinnedPieces[Us] = pos.pinned_pieces(Us);
-

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


@@ -289,7 +280,7 @@ namespace {
           : Pt ==   ROOK ? attacks_bb<  ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
                          : pos.attacks_from<Pt>(s);
 
           : Pt ==   ROOK ? attacks_bb<  ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
                          : pos.attacks_from<Pt>(s);
 

-        if (ei.pinnedPieces[Us] & s)
+        if (pos.pinned_pieces(Us) & s)

             b &= LineBB[pos.square<KING>(Us)][s];
 
         ei.attackedBy2[Us] |= ei.attackedBy[Us][ALL_PIECES] & b;
             b &= LineBB[pos.square<KING>(Us)][s];
 
         ei.attackedBy2[Us] |= ei.attackedBy[Us][ALL_PIECES] & b;


@@ -316,12 +307,12 @@ namespace {
             // Bonus for outpost squares
             bb = OutpostRanks & ~ei.pe->pawn_attacks_span(Them);
             if (bb & s)
             // Bonus for outpost squares
             bb = OutpostRanks & ~ei.pe->pawn_attacks_span(Them);
             if (bb & s)

-                score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)];
+                score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)] * 2;

             else
             {
                 bb &= b & ~pos.pieces(Us);
                 if (bb)
             else
             {
                 bb &= b & ~pos.pieces(Us);
                 if (bb)

-                   score += ReachableOutpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)];
+                   score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)];

             }
 
             // Bonus when behind a pawn
             }
 
             // Bonus when behind a pawn


@@ -435,7 +426,7 @@ namespace {
         kingDanger =  std::min(807, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
                     + 101 * ei.kingAdjacentZoneAttacksCount[Them]
                     + 235 * popcount(undefended)
         kingDanger =  std::min(807, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
                     + 101 * ei.kingAdjacentZoneAttacksCount[Them]
                     + 235 * popcount(undefended)

-                    + 134 * (popcount(b) + !!ei.pinnedPieces[Us])
+                    + 134 * (popcount(b) + !!pos.pinned_pieces(Us))

                     - 717 * !pos.count<QUEEN>(Them)
                     -   7 * mg_value(score) / 5 - 5;
 
                     - 717 * !pos.count<QUEEN>(Them)
                     -   7 * mg_value(score) / 5 - 5;
 


@@ -798,18 +789,6 @@ namespace {
     return sf;
   }
 
     return sf;
   }
 

-
-  Value lazy_eval(Value mg, Value eg) {
-
-    if (mg > LazyEval && eg > LazyEval)
-        return  LazyEval + ((mg + eg) / 2 - LazyEval) / 4;
-
-    else if (mg < -LazyEval && eg < -LazyEval)
-        return -LazyEval + ((mg + eg) / 2 + LazyEval) / 4;
-
-    return VALUE_ZERO;
-  }
-

 } // namespace
 
 
 } // namespace
 
 


@@ -822,6 +801,7 @@ Value Eval::evaluate(const Position& pos) {
   assert(!pos.checkers());
 
   Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO };
   assert(!pos.checkers());
 
   Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO };

+  Value v;

   EvalInfo ei;
 
   // Probe the material hash table
   EvalInfo ei;
 
   // Probe the material hash table


@@ -841,11 +821,10 @@ Value Eval::evaluate(const Position& pos) {
   ei.pe = Pawns::probe(pos);
   score += ei.pe->pawns_score();
 
   ei.pe = Pawns::probe(pos);
   score += ei.pe->pawns_score();
 

-  // We have taken into account all cheap evaluation terms.
-  // If score exceeds a threshold return a lazy evaluation.
-  Value lazy = lazy_eval(mg_value(score), eg_value(score));
-  if (lazy)
-      return pos.side_to_move() == WHITE ? lazy : -lazy;
+  // Early exit if score is high
+  v = (mg_value(score) + eg_value(score)) / 2;
+  if (abs(v) > LazyThreshold)
+     return pos.side_to_move() == WHITE ? v : -v;

 
   // Initialize attack and king safety bitboards
   eval_init<WHITE>(pos, ei);
 
   // Initialize attack and king safety bitboards
   eval_init<WHITE>(pos, ei);


@@ -880,8 +859,8 @@ Value Eval::evaluate(const Position& pos) {
   ScaleFactor sf = evaluate_scale_factor(pos, ei, eg_value(score));
 
   // Interpolate between a middlegame and a (scaled by 'sf') endgame score
   ScaleFactor sf = evaluate_scale_factor(pos, ei, eg_value(score));
 
   // Interpolate between a middlegame and a (scaled by 'sf') endgame score

-  Value v =  mg_value(score) * int(ei.me->game_phase())
-           + eg_value(score) * int(PHASE_MIDGAME - ei.me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
+  v =  mg_value(score) * int(ei.me->game_phase())
+     + eg_value(score) * int(PHASE_MIDGAME - ei.me->game_phase()) * sf / SCALE_FACTOR_NORMAL;

 
   v /= int(PHASE_MIDGAME);
 
 
   v /= int(PHASE_MIDGAME);