Tweak connected pawns seed[] array values

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 0f6430b90f1616c127a397cf5b832a809c8b88b8..f76b0e69b9dc0c4229fb23a2e840fac092a5d981 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -32,16 +32,13 @@ namespace {
   #define S(mg, eg) make_score(mg, eg)
 
   // Isolated pawn penalty by opposed flag
-  const Score Isolated[] = { S(45, 40), S(30, 27) };
+  const Score Isolated[] = { S(27, 30), S(13, 18) };
 
   // Backward pawn penalty by opposed flag
-  const Score Backward[] = { S(56, 33), S(41, 19) };
+  const Score Backward[] = { S(40, 26), S(24, 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];
+  // Connected pawn bonus by opposed, phalanx, #support and rank
+  Score Connected[2][2][3][RANK_NB];
 
   // Doubled pawn penalty
   const Score Doubled = S(18, 38);
@@ -99,7 +96,7 @@ namespace {
     const Square Left  = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
 
     Bitboard b, neighbours, stoppers, doubled, supported, phalanx;
-    Bitboard lever, leverPush, connected;
+    Bitboard lever, leverPush;
     Square s;
     bool opposed, backward;
     Score score = SCORE_ZERO;
@@ -126,7 +123,7 @@ namespace {
         e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s);
 
         // Flag the pawn
-        opposed    = theirPawns & forward_bb(Us, s);
+        opposed    = theirPawns & forward_file_bb(Us, s);
         stoppers   = theirPawns & passed_pawn_mask(Us, s);
         lever      = theirPawns & PawnAttacks[Us][s];
         leverPush  = theirPawns & PawnAttacks[Us][s + Up];
@@ -134,7 +131,6 @@ namespace {
         neighbours = ourPawns   & adjacent_files_bb(f);
         phalanx    = neighbours & rank_bb(s);
         supported  = neighbours & rank_bb(s - Up);
-        connected  = supported | phalanx;
 
         // A pawn is backward when it is behind all pawns of the same color on the
         // adjacent files and cannot be safely advanced.
@@ -150,7 +146,7 @@ namespace {
             // stopper on adjacent file which controls the way to that rank.
             backward = (b | shift<Up>(b & adjacent_files_bb(f))) & stoppers;
 
-            assert(!backward || !(pawn_attack_span(Them, s + Up) & neighbours));
+            assert(!(backward && (forward_ranks_bb(Them, s + Up) & neighbours)));
         }
 
         // Passed pawns will be properly scored in evaluation because we need
@@ -158,7 +154,7 @@ namespace {
         // which could become passed after one or two pawn pushes when are
         // not attacked more times than defended.
         if (   !(stoppers ^ lever ^ leverPush)
-            && !(ourPawns & forward_bb(Us, s))
+            && !(ourPawns & forward_file_bb(Us, s))
             && popcount(supported) >= popcount(lever)
             && popcount(phalanx)   >= popcount(leverPush))
             e->passedPawns[Us] |= s;
@@ -173,18 +169,15 @@ namespace {
         }
 
         // Score this pawn
-        if (!neighbours)
+        if (supported | phalanx)
+            score += Connected[opposed][!!phalanx][popcount(supported)][relative_rank(Us, s)];
+
+        else if (!neighbours)
             score -= Isolated[opposed];
 
         else if (backward)
             score -= Backward[opposed];
 
-        else if (!supported)
-            score -= Unsupported;
-
-        if (connected)
-            score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
-
         if (doubled && !supported)
             score -= Doubled;
 
@@ -205,16 +198,17 @@ namespace Pawns {
 
 void init() {
 
-  static const int Seed[RANK_NB] = { 0, 8, 19, 13, 71, 94, 169, 324 };
+  static const int Seed[RANK_NB] = { 0, 13, 24, 18, 76, 100, 175, 330 };
 
   for (int opposed = 0; opposed <= 1; ++opposed)
       for (int phalanx = 0; phalanx <= 1; ++phalanx)
-          for (int apex = 0; apex <= 1; ++apex)
+          for (int support = 0; support <= 2; ++support)
               for (Rank r = RANK_2; r < RANK_8; ++r)
   {
-      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 * (r-2) / 4);
+      int v = 17 * support;
+      v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
+
+      Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4);
   }
 }
 
@@ -250,7 +244,7 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
 
   enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked };
 
-  Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, rank_of(ksq)) | rank_bb(ksq));
+  Bitboard b = pos.pieces(PAWN) & (forward_ranks_bb(Us, ksq) | rank_bb(ksq));
   Bitboard ourPawns = b & pos.pieces(Us);
   Bitboard theirPawns = b & pos.pieces(Them);
   Value safety = MaxSafetyBonus;
@@ -261,7 +255,7 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
       b = ourPawns & file_bb(f);
       Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
 
-      b  = theirPawns & file_bb(f);
+      b = theirPawns & file_bb(f);
       Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
 
       int d = std::min(f, FILE_H - f);