Bonus for loose enemies

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 826e860a5c22d3441424f63fd674c2aaa5b624d1..a63b40ae98403a69153a2782c1bd066c75f2d153 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -168,8 +168,8 @@ namespace {
   // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns.
   // We don't use a Score because we process the two components independently.
   const Value Passed[][RANK_NB] = {
-    { V(0), V( 1), V(26), V(68), V(161), V(247) },
-    { V(7), V(14), V(38), V(64), V(137), V(193) }
+    { V(5), V( 5), V(31), V(73), V(166), V(252) },
+    { V(7), V(14), V(38), V(73), V(166), V(252) }
   };
 
   // PassedFile[File] contains a bonus according to the file of a passed pawn
@@ -185,6 +185,7 @@ namespace {
   const Score TrappedRook         = S(92,  0);
   const Score Checked             = S(20, 20);
   const Score ThreatByHangingPawn = S(70, 63);
+  const Score LooseEnemies        = S( 0, 25);
   const Score Hanging             = S(48, 28);
   const Score ThreatByPawnPush    = S(31, 19);
   const Score Unstoppable         = S( 0, 20);
@@ -424,36 +425,20 @@ namespace {
         b2 = pos.attacks_from<BISHOP>(ksq) & safe;
 
         // Enemy queen safe checks
-        b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
-        if (b)
-        {
-            attackUnits += QueenCheck * popcount<Max15>(b);
-            score -= Checked;
-        }
+        if ((b1 | b2) & ei.attackedBy[Them][QUEEN])
+            attackUnits += QueenCheck, score -= Checked;
 
         // Enemy rooks safe checks
-        b = b1 & ei.attackedBy[Them][ROOK];
-        if (b)
-        {
-            attackUnits += RookCheck * popcount<Max15>(b);
-            score -= Checked;
-        }
+        if (b1 & ei.attackedBy[Them][ROOK])
+            attackUnits += RookCheck, score -= Checked;
 
         // Enemy bishops safe checks
-        b = b2 & ei.attackedBy[Them][BISHOP];
-        if (b)
-        {
-            attackUnits += BishopCheck * popcount<Max15>(b);
-            score -= Checked;
-        }
+        if (b2 & ei.attackedBy[Them][BISHOP])
+            attackUnits += BishopCheck, score -= Checked;
 
         // Enemy knights safe checks
-        b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
-        if (b)
-        {
-            attackUnits += KnightCheck * popcount<Max15>(b);
-            score -= Checked;
-        }
+        if (pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe)
+            attackUnits += KnightCheck, score -= Checked;
 
         // Finally, extract the king danger score from the KingDanger[]
         // array and subtract the score from the evaluation.
@@ -467,7 +452,7 @@ namespace {
   }
 
 
-  // evaluate_threats() assigns bonuses according to the types of the attacking 
+  // evaluate_threats() assigns bonuses according to the types of the attacking
   // and the attacked pieces.
 
   template<Color Us, bool DoTrace>
@@ -485,6 +470,11 @@ namespace {
     Bitboard b, weak, defended, safeThreats;
     Score score = SCORE_ZERO;
 
+    // Small bonus if the opponent has loose pawns or pieces
+    if (   (pos.pieces(Them) ^ pos.pieces(Them, QUEEN, KING))
+        & ~(ei.attackedBy[Us][ALL_PIECES] | ei.attackedBy[Them][ALL_PIECES]))
+        score += LooseEnemies;
+
     // Non-pawn enemies attacked by a pawn
     weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Us][PAWN];
 
@@ -615,10 +605,10 @@ namespace {
                 else if (defendedSquares & blockSq)
                     k += 4;
 
-                mbonus += k * rr * 3 / 4, ebonus += k * rr;
+                mbonus += k * rr, ebonus += k * rr;
             }
             else if (pos.pieces(Us) & blockSq)
-                mbonus += (rr * 3 + r * 2 + 3) * 3 / 4, ebonus += rr + r * 2;
+                mbonus += rr + r * 2, ebonus += rr + r * 2;
         } // rr != 0
 
         if (pos.count<PAWN>(Us) < pos.count<PAWN>(Them))
@@ -679,11 +669,12 @@ namespace {
   // status of the players.
   Score evaluate_initiative(const Position& pos, int asymmetry, Value eg) {
 
-    int kingDistance = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
+    int kingDistance =  distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
+                      - distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
     int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
 
     // Compute the initiative bonus for the attacking side
-    int initiative = 8 * (pawns + asymmetry + kingDistance - 15);
+    int initiative = 8 * (asymmetry + kingDistance - 15) + 12 * pawns;
 
     // Now apply the bonus: note that we find the attacking side by extracting
     // the sign of the endgame value, and that we carefully cap the bonus so