Do lmr for more captures

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index ea54e271390e68e5a0f65cbb63537628ef0fd6d9..7760f70538d411e445324d2df749f6510c084dee 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -135,10 +135,11 @@ namespace {
   constexpr Score KnightOnQueen      = S( 16, 12);
   constexpr Score LongDiagonalBishop = S( 45,  0);
   constexpr Score MinorBehindPawn    = S( 18,  3);
-  constexpr Score Outpost            = S( 32, 10);
+  constexpr Score Outpost            = S( 30, 21);
   constexpr Score PassedFile         = S( 11,  8);
   constexpr Score PawnlessFlank      = S( 17, 95);
   constexpr Score RestrictedPiece    = S(  7,  7);
+  constexpr Score ReachableOutpost   = S( 32, 10);
   constexpr Score RookOnQueenFile    = S(  7,  6);
   constexpr Score SliderOnQueen      = S( 59, 18);
   constexpr Score ThreatByKing       = S( 24, 89);
@@ -295,7 +296,7 @@ namespace {
                 score += Outpost * (Pt == KNIGHT ? 2 : 1);
 
             else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
-                score += Outpost;
+                score += ReachableOutpost;
 
             // Knight and Bishop bonus for being right behind a pawn
             if (shift<Down>(pos.pieces(PAWN)) & s)
@@ -375,7 +376,7 @@ namespace {
     constexpr Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
                                            : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
 
-    Bitboard weak, b1, b2, safe, unsafeChecks = 0;
+    Bitboard weak, b1, b2, b3, safe, unsafeChecks = 0;
     Bitboard rookChecks, queenChecks, bishopChecks, knightChecks;
     int kingDanger = 0;
     const Square ksq = pos.square<KING>(Us);
@@ -434,19 +435,22 @@ namespace {
     else
         unsafeChecks |= knightChecks;
 
-    // Find the squares that opponent attacks in our king flank, and the squares
-    // which are attacked twice in that flank.
+    // 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 kingFlankAttacks = popcount(b1) + popcount(b2);
+    int kingFlankAttack = popcount(b1) + popcount(b2);
+    int kingFlankDefense = popcount(b3);
 
     kingDanger +=        kingAttackersCount[Them] * kingAttackersWeight[Them]
                  + 185 * popcount(kingRing[Us] & weak)
                  + 148 * popcount(unsafeChecks)
                  +  98 * popcount(pos.blockers_for_king(Us))
                  +  69 * kingAttacksCount[Them]
-                 +   3 * kingFlankAttacks * kingFlankAttacks / 8
+                 +   4 * (kingFlankAttack - kingFlankDefense)
+                 +   3 * kingFlankAttack * kingFlankAttack / 8
                  +       mg_value(mobility[Them] - mobility[Us])
                  - 873 * !pos.count<QUEEN>(Them)
                  - 100 * bool(attackedBy[Us][KNIGHT] & attackedBy[Us][KING])
@@ -463,7 +467,7 @@ namespace {
         score -= PawnlessFlank;
 
     // Penalty if king flank is under attack, potentially moving toward the king
-    score -= FlankAttacks * kingFlankAttacks;
+    score -= FlankAttacks * kingFlankAttack;
 
     if (T)
         Trace::add(KING, Us, score);