Rank-based outposts

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index c1640d945d0d115bca1355da9cbcb57896f5e9e3..07bacf8dcc0f0e40551a99df3e9866b88d9f98ba 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -125,6 +125,11 @@ namespace {
   constexpr Score PassedRank[RANK_NB] = {
     S(0, 0), S(10, 28), S(17, 33), S(15, 41), S(62, 72), S(168, 177), S(276, 260)
   };
+  
+  // OutpostRank[Rank] contains a bonus according to the rank of the outpost
+  constexpr Score OutpostRank[RANK_NB] = {
+    S(0, 0), S(0, 0), S(0, 0), S(28, 18), S(30, 24), S(32, 19)
+  };
 
   // Assorted bonuses and penalties
   constexpr Score BishopPawns        = S(  3,  7);
@@ -235,15 +240,9 @@ namespace {
     attackedBy2[Us] = dblAttackByPawn | (attackedBy[Us][KING] & attackedBy[Us][PAWN]);
 
     // Init our king safety tables
-    kingRing[Us] = attackedBy[Us][KING];
-    if (relative_rank(Us, ksq) == RANK_1)
-        kingRing[Us] |= shift<Up>(kingRing[Us]);
-
-    if (file_of(ksq) == FILE_H)
-        kingRing[Us] |= shift<WEST>(kingRing[Us]);
-
-    else if (file_of(ksq) == FILE_A)
-        kingRing[Us] |= shift<EAST>(kingRing[Us]);
+    Square s = make_square(clamp(file_of(ksq), FILE_B, FILE_G),
+                           clamp(rank_of(ksq), RANK_2, RANK_7));
+    kingRing[Us] = s | PseudoAttacks[KING][s];
 
     kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them));
     kingAttacksCount[Them] = kingAttackersWeight[Them] = 0;
@@ -297,8 +296,8 @@ namespace {
         {
             // Bonus if piece is on an outpost square or can reach one
             bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
-            if (bb & s)
-                score += Outpost * (Pt == KNIGHT ? 2 : 1);
+            if (s & bb)
+                score += OutpostRank[relative_rank(Us, s)] * (Pt == KNIGHT ? 2 : 1);
 
             else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
                 score += Outpost;
@@ -719,10 +718,10 @@ namespace {
     int complexity =   9 * pe->passed_count()
                     + 11 * pos.count<PAWN>()
                     +  9 * outflanking
-                    + 18 * pawnsOnBothFlanks
-                    + 49 * !pos.non_pawn_material()
-                    - 36 * almostUnwinnable
-                    -103 ;
+                    + 21 * pawnsOnBothFlanks
+                    + 51 * !pos.non_pawn_material()
+                    - 43 * almostUnwinnable
+                    - 95 ;
 
     // Now apply the bonus: note that we find the attacking side by extracting the
     // sign of the midgame or endgame values, and that we carefully cap the bonus