Pawn flank attacks

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 245ba0c6a90680403a785a5911f4885417f20704..6e564c9ddae2c6e6ea21829a085bfd6deab22c26 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -37,9 +37,8 @@ namespace {
   // Backward pawn penalty by opposed flag
   const Score Backward[2] = { S(56, 33), S(41, 19) };
 
-  // Unsupported pawn penalty for pawns which are neither isolated or backward,
-  // by number of pawns it supports [less than 2 / exactly 2].
-  const Score Unsupported[2] = { S(17, 8), S(21, 12) };
+  // Unsupported pawn penalty for pawns which are neither isolated or backward
+  const Score Unsupported = S(17, 8);
 
   // Connected pawn bonus by opposed, phalanx, twice supported and rank
   Score Connected[2][2][2][RANK_NB];
@@ -55,30 +54,31 @@ namespace {
 
   // Weakness of our pawn shelter in front of the king by [distance from edge][rank]
   const Value ShelterWeakness[][RANK_NB] = {
-    { V( 97), V(21), V(26), V(51), V(87), V( 89), V( 99) },
-    { V(120), V( 0), V(28), V(76), V(88), V(103), V(104) },
-    { V(101), V( 7), V(54), V(78), V(77), V( 92), V(101) },
-    { V( 80), V(11), V(44), V(68), V(87), V( 90), V(119) }
+    { V(100), V(20), V(10), V(46), V(82), V( 86), V( 98) },
+    { V(116), V( 4), V(28), V(87), V(94), V(108), V(104) },
+    { V(109), V( 1), V(59), V(87), V(62), V( 91), V(116) },
+    { V( 75), V(12), V(43), V(59), V(90), V( 84), V(112) }
   };
 
   // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]
   const Value StormDanger[][4][RANK_NB] = {
-    { { V( 0),  V(  67), V( 134), V(38), V(32) },
-      { V( 0),  V(  57), V( 139), V(37), V(22) },
-      { V( 0),  V(  43), V( 115), V(43), V(27) },
-      { V( 0),  V(  68), V( 124), V(57), V(32) } },
-    { { V(20),  V(  43), V( 100), V(56), V(20) },
-      { V(23),  V(  20), V(  98), V(40), V(15) },
-      { V(23),  V(  39), V( 103), V(36), V(18) },
-      { V(28),  V(  19), V( 108), V(42), V(26) } },
-    { { V( 0),  V(   0), V(  75), V(14), V( 2) },
-      { V( 0),  V(   0), V( 150), V(30), V( 4) },
-      { V( 0),  V(   0), V( 160), V(22), V( 5) },
-      { V( 0),  V(   0), V( 166), V(24), V(13) } },
-    { { V( 0),  V(-283), V(-281), V(57), V(31) },
-      { V( 0),  V(  58), V( 141), V(39), V(18) },
-      { V( 0),  V(  65), V( 142), V(48), V(32) },
-      { V( 0),  V(  60), V( 126), V(51), V(19) } }
+    { { V( 4),  V(  73), V( 132), V(46), V(31) },
+      { V( 1),  V(  64), V( 143), V(26), V(13) },
+      { V( 1),  V(  47), V( 110), V(44), V(24) },
+      { V( 0),  V(  72), V( 127), V(50), V(31) } },
+    { { V(22),  V(  45), V( 104), V(62), V( 6) },
+      { V(31),  V(  30), V(  99), V(39), V(19) },
+      { V(23),  V(  29), V(  96), V(41), V(15) },
+      { V(21),  V(  23), V( 116), V(41), V(15) } },
+    { { V( 0),  V(   0), V(  79), V(23), V( 1) },
+      { V( 0),  V(   0), V( 148), V(27), V( 2) },
+      { V( 0),  V(   0), V( 161), V(16), V( 1) },
+      { V( 0),  V(   0), V( 171), V(22), V(15) } },
+    { { V( 0),  V(-290), V(-274), V(57), V(41) },
+      { V( 0),  V(  60), V( 144), V(39), V(13) },
+      { V( 0),  V(  65), V( 141), V(41), V(34) },
+      { V( 0),  V(  53), V( 127), V(56), V(14) } }
+
   };
 
   // Max bonus for king safety. Corresponds to start position with all the pawns
@@ -163,7 +163,7 @@ namespace {
             score -= Backward[opposed];
 
         else if (!supported)
-            score -= Unsupported[more_than_one(neighbours & pawnAttacksBB[s])];
+            score -= Unsupported;
 
         if (connected)
             score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
@@ -197,7 +197,7 @@ void init() {
   {
       int v = (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
       v += (apex ? v / 2 : 0);
-      Connected[opposed][phalanx][apex][r] = make_score(v, v * 5 / 8);
+      Connected[opposed][phalanx][apex][r] = make_score(v, v * (r-2) / 4);
   }
 }