Further simplify KingDanger init

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index e03dfb94fb7fa28dcd18f43710f10b7c5ac98ed1..9af22264b89ff00fbdd247eb33468072d750a962 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -162,6 +162,7 @@ namespace {
   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
@@ -545,14 +546,18 @@ namespace {
             score += more_than_one(b) ? KingOnMany : KingOnOne;
     }
 
-    // Add bonus for safe pawn pushes which attacks an enemy piece
+    // 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][PAWN] | ~ei.attackedBy[Them][ALL_PIECES]);
+        & (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];
@@ -899,14 +904,14 @@ 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]);
     }
   }