Re-add "Further increase safe checks bonus"

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index d65b0418f0145f448c3d37dff8ecb7262c86fdaf..b74f0659b24a371a92a6184ce5c73a50ea57ae7c 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -52,10 +52,16 @@ namespace {
     S(33, 31), S(33, 31), S(29, 31), S(20, 28) }};
 
   // Pawn chain membership bonus by file
-  const Score ChainMember[FILE_NB] = {
-    S(11,-1), S(13,-1), S(13,-1), S(14,-1),
-    S(14,-1), S(13,-1), S(13,-1), S(11,-1)
-  };
+  const Score ChainMember[FILE_NB][RANK_NB] = {
+    { S(0, 0), S(14, 0), S(16, 4), S(18,  9), S(56, 56), S(104, 208), S(236, 472) }, 
+    { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, 
+    { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, 
+    { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(66, 66), S(118, 236), S(254, 508) }, 
+    { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(66, 66), S(118, 236), S(254, 508) }, 
+    { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, 
+    { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(60, 60), S(108, 216), S(240, 480) }, 
+    { S(0, 0), S(14, 0), S(16, 4), S(18,  9), S(56, 56), S(104, 208), S(236, 472) }
+  }; 
 
   // Candidate passed pawn bonus by rank
   const Score CandidatePassed[RANK_NB] = {
@@ -92,6 +98,7 @@ namespace {
     Bitboard b;
     Square s;
     File f;
+    Rank r;
     bool passed, isolated, doubled, opposed, chain, backward, candidate;
     Score value = SCORE_ZERO;
     const Square* pl = pos.list<PAWN>(Us);
@@ -99,7 +106,7 @@ namespace {
     Bitboard ourPawns = pos.pieces(Us, PAWN);
     Bitboard theirPawns = pos.pieces(Them, PAWN);
 
-    e->passedPawns[Us] = 0;
+    e->passedPawns[Us] = e->candidatePawns[Us] = 0;
     e->kingSquares[Us] = SQ_NONE;
     e->semiopenFiles[Us] = 0xFF;
     e->pawnAttacks[Us] = shift_bb<Right>(ourPawns) | shift_bb<Left>(ourPawns);
@@ -112,6 +119,7 @@ namespace {
         assert(pos.piece_on(s) == make_piece(Us, PAWN));
 
         f = file_of(s);
+        r = relative_rank(Us, s);
 
         // This file cannot be semi-open
         e->semiopenFiles[Us] &= ~(1 << f);
@@ -176,10 +184,15 @@ namespace {
             value -= Backward[opposed][f];
 
         if (chain)
-            value += ChainMember[f];
+            value += opposed ? ChainMember[f][r] / 2 : ChainMember[f][r];
 
         if (candidate)
-            value += CandidatePassed[relative_rank(Us, s)];
+        {
+            value += CandidatePassed[r];
+
+            if (!doubled)
+                e->candidatePawns[Us] |= s;
+        }
     }
 
     return value;
@@ -222,7 +235,7 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
   Rank rkUs, rkThem;
   File kf = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
 
-  for (int f = kf - 1; f <= kf + 1; f++)
+  for (int f = kf - 1; f <= kf + 1; ++f)
   {
       b = ourPawns & FileBB[f];
       rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;