Introduce pinning bonus

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 32469a916e8cc59b052ac9e3d1bca2f83c74900e..83a0c9123c708b2e739ecb9a737f51fa2ab1fa9d 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -18,7 +18,6 @@
 */
 
 #include <cassert>
-#include <iostream>
 #include <iomanip>
 #include <sstream>
 #include <algorithm>
@@ -156,8 +155,8 @@ namespace {
   const Score QueenOn7thBonus = make_score(27, 54);
 
   // Rooks on open files (modified by Joona Kiiski)
-  const Score RookOpenFileBonus = make_score(43, 43);
-  const Score RookHalfOpenFileBonus = make_score(19, 19);
+  const Score RookOpenFileBonus = make_score(43, 21);
+  const Score RookHalfOpenFileBonus = make_score(19, 10);
 
   // Penalty for rooks trapped inside a friendly king which has lost the
   // right to castle.
@@ -454,7 +453,7 @@ namespace {
 
     // Increase bonus if supported by pawn, especially if the opponent has
     // no minor piece which can exchange the outpost piece.
-    if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
+    if (bonus && (ei.attackedBy[Us][PAWN] & s))
     {
         if (   !pos.pieces(KNIGHT, Them)
             && !(same_color_squares(s) & pos.pieces(BISHOP, Them)))
@@ -488,16 +487,14 @@ namespace {
         if (Piece == KNIGHT || Piece == QUEEN)
             b = pos.attacks_from<Piece>(s);
         else if (Piece == BISHOP)
-            b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
+            b = attacks_bb<BISHOP>(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
         else if (Piece == ROOK)
-            b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
+            b = attacks_bb<ROOK>(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
         else
             assert(false);
 
-        // Update attack info
         ei.attackedBy[Us][Piece] |= b;
 
-        // King attacks
         if (b & ei.kingRing[Them])
         {
             ei.kingAttackersCount[Us]++;
@@ -507,15 +504,26 @@ namespace {
                 ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
         }
 
-        // Mobility
         mob = (Piece != QUEEN ? popcount<Max15>(b & mobilityArea)
                               : popcount<Full >(b & mobilityArea));
 
         mobility += MobilityBonus[Piece][mob];
 
+        // Add a bonus if a slider is pinning an enemy piece
+        if (   (Piece == BISHOP || Piece == ROOK || Piece == QUEEN)
+            && (PseudoAttacks[Piece][pos.king_square(Them)] & s))
+        {
+            b = BetweenBB[s][pos.king_square(Them)] & pos.occupied_squares();
+
+            assert(b);
+
+            if (!(b & (b - 1)) && (b & pos.pieces(Them)))
+                score += ThreatBonus[Piece][type_of(pos.piece_on(first_1(b)))] / 2;
+        }
+
         // Decrease score if we are attacked by an enemy pawn. Remaining part
         // of threat evaluation must be done later when we have full attack info.
-        if (bit_is_set(ei.attackedBy[Them][PAWN], s))
+        if (ei.attackedBy[Them][PAWN] & s)
             score -= ThreatenedByPawnPenalty[Piece];
 
         // Bishop and knight outposts squares
@@ -945,7 +953,7 @@ namespace {
         // Check if (without even considering any obstacles) we're too far away or doubled
         if (   pliesToQueen[winnerSide] + 3 <= pliesToGo
             || (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide)))
-            clear_bit(&candidates, s);
+            candidates ^= s;
     }
 
     // If any candidate is already a passed pawn it _may_ promote in time. We give up.