Remove penalty for knight when few enemy pawns

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index b1422ac67eccb50fefdebde17d7396d01b0542db..f7a59de69319c9bff7192b739e544e2ba5e76b65 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -166,7 +166,6 @@ namespace {
   const Score RookOpenFile     = make_score(43, 21);
   const Score RookSemiopenFile = make_score(19, 10);
   const Score BishopPawns      = make_score( 8, 12);
-  const Score KnightPawns      = make_score( 8,  4);
   const Score MinorBehindPawn  = make_score(16,  0);
   const Score UndefendedMinor  = make_score(25, 10);
   const Score TrappedRook      = make_score(90,  0);
@@ -349,10 +348,6 @@ namespace {
             if (Pt == BISHOP)
                 score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
 
-            // Penalty for knight when there are few enemy pawns
-            if (Pt == KNIGHT)
-                score -= KnightPawns * std::max(5 - pos.count<PAWN>(Them), 0);
-
             // Bishop and knight outposts squares
             if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
                 score += evaluate_outposts<Pt, Us>(pos, ei, s);
@@ -702,9 +697,7 @@ namespace {
   template<Color Us>
   int evaluate_space(const Position& pos, const EvalInfo& ei) {
 
-    const Color  Them     = (Us == WHITE ? BLACK    : WHITE);
-    const Square Down     = (Us == WHITE ? DELTA_S  : DELTA_N);
-    const Square DownDown = (Us == WHITE ? DELTA_SS : DELTA_NN);
+    const Color Them = (Us == WHITE ? BLACK : WHITE);
 
     // Find the safe squares for our pieces inside the area defined by
     // SpaceMask[]. A square is unsafe if it is attacked by an enemy
@@ -716,8 +709,8 @@ namespace {
 
     // Find all squares which are at most three squares behind some friendly pawn
     Bitboard behind = pos.pieces(Us, PAWN);
-    behind |= shift_bb<    Down>(behind);
-    behind |= shift_bb<DownDown>(behind);
+    behind |= (Us == WHITE ? behind >>  8 : behind <<  8);
+    behind |= (Us == WHITE ? behind >> 16 : behind << 16);
 
     // Since SpaceMask[Us] is fully on our half of the board
     assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);