X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=77096c9b30f62d581d52c944051865913154bef9;hp=153e6eaeb987e5e77ba2f8dadd135b7413711ad9;hb=fce799294c124a096b15539bb863788ec3a68cf6;hpb=ddccb5355cabb7d1a9bf2c0fe3c51b3da0234260

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 153e6eae..77096c9b 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -61,11 +61,11 @@ namespace {
     // KingAttackWeights array.
     int kingAttackersWeight[COLOR_NB];
 
-    // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
-    // directly adjacent to the king of the given color. Pieces which attack
-    // more than one square are counted multiple times. For instance, if black's
-    // king is on g8 and there's a white knight on g5, this knight adds
-    // 2 to kingAdjacentZoneAttacksCount[BLACK].
+    // kingAdjacentZoneAttacksCount[color] is the number of attacks by the given
+    // color to squares directly adjacent to the enemy king. Pieces which attack
+    // more than one square are counted multiple times. For instance, if there is
+    // a white knight on g5 and black's king is on g8, this white knight adds 2
+    // to kingAdjacentZoneAttacksCount[WHITE].
     int kingAdjacentZoneAttacksCount[COLOR_NB];
 
     Bitboard pinnedPieces[COLOR_NB];
@@ -162,6 +162,8 @@ namespace {
   const Score TrappedRook        = S(92,  0);
   const Score Unstoppable        = S( 0, 20);
   const Score Hanging            = S(31, 26);
+  const Score PawnAttackThreat   = S(20, 20);
+  const Score PawnSafePush       = S( 5,  5);
 
   // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
   // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
@@ -412,10 +414,10 @@ namespace {
         // attacked and undefended squares around our king and the quality of
         // the pawn shelter (current 'score' value).
         attackUnits =  std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
-                     + 8 * ei.kingAdjacentZoneAttacksCount[Them]
+                     +  8 * ei.kingAdjacentZoneAttacksCount[Them]
                      + 25 * popcount<Max15>(undefended)
-                     +  11 * (ei.pinnedPieces[Us] != 0)
-                     - mg_value(score) * 31 / 256
+                     + 11 * (ei.pinnedPieces[Us] != 0)
+                     - mg_value(score) / 8
                      - !pos.count<QUEEN>(Them) * 60;
 
         // Analyse the enemy's safe queen contact checks. Firstly, find the
@@ -492,7 +494,12 @@ namespace {
   template<Color Us, bool Trace>
   Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
 
-    const Color Them = (Us == WHITE ? BLACK : WHITE);
+    const Color Them        = (Us == WHITE ? BLACK    : WHITE);
+    const Square Up         = (Us == WHITE ? DELTA_N  : DELTA_S);
+    const Square Left       = (Us == WHITE ? DELTA_NW : DELTA_SE);
+    const Square Right      = (Us == WHITE ? DELTA_NE : DELTA_SW);
+    const Bitboard TRank2BB = (Us == WHITE ? Rank2BB  : Rank7BB);
+    const Bitboard TRank7BB = (Us == WHITE ? Rank7BB  : Rank2BB);
 
     enum { Defended, Weak };
     enum { Minor, Major };
@@ -541,6 +548,25 @@ namespace {
             score += more_than_one(b) ? KingOnMany : KingOnOne;
     }
 
+    // Add a small bonus for safe pawn pushes
+    b = pos.pieces(Us, PAWN) & ~TRank7BB;
+    b = shift_bb<Up>(b | (shift_bb<Up>(b & TRank2BB) & ~pos.pieces()));
+
+    b &=  ~pos.pieces()
+        & ~ei.attackedBy[Them][PAWN]
+        & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
+
+    if (b)
+        score += popcount<Full>(b) * PawnSafePush;
+
+    // Add another bonus if the pawn push attacks an enemy piece
+    b =  (shift_bb<Left>(b) | shift_bb<Right>(b))
+       &  pos.pieces(Them)
+       & ~ei.attackedBy[Us][PAWN];
+
+    if (b)
+        score += popcount<Max15>(b) * PawnAttackThreat;
+
     if (Trace)
         Tracing::write(Tracing::THREAT, Us, score);
 
@@ -891,14 +917,14 @@ namespace Eval {
 
   void init() {
 
-    const double MaxSlope = 8.7;
-    const double Peak = 1280;
-    double t = 0.0;
+    const int MaxSlope = 8700;
+    const int Peak = 1280000;
+    int t = 0;
 
-    for (int i = 1; i < 400; ++i)
+    for (int i = 0; i < 400; ++i)
     {
-        t = std::min(Peak, std::min(0.027 * i * i, t + MaxSlope));
-        KingDanger[i] = apply_weight(make_score(int(t), 0), Weights[KingSafety]);
+        t = std::min(Peak, std::min(i * i * 27, t + MaxSlope));
+        KingDanger[i] = apply_weight(make_score(t / 1000, 0), Weights[KingSafety]);
     }
   }