MobilityArea (simplified)

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 563e707ffe48df1c01d0e65dd5b4cbb7fb03e2f9..37cdce997c8ec014484c5ab865d50c89751a4d62 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -124,23 +124,11 @@ namespace {
       S( 94, 99), S( 96,100), S(99,111), S(99,112) }
   };
 
-  // Outpost[Bishop/Knight][Square] contains bonuses for knights and bishops
-  // outposts, indexed by piece type and square (from white's point of view).
-  const Value Outpost[][SQUARE_NB] = {
-  {// A     B     C     D     E     F     G     H
-    V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
-    V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
-    V(0), V(0), V(3), V(9), V(9), V(3), V(0), V(0),
-    V(0), V(4),V(18),V(25),V(25),V(18), V(4), V(0),
-    V(4), V(9),V(29),V(38),V(38),V(29), V(9), V(4),
-    V(2), V(9),V(19),V(15),V(15),V(19), V(9), V(2) },
-  {
-    V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops
-    V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
-    V(2), V(4), V(3), V(8), V(8), V(3), V(4), V(2),
-    V(1), V(9), V(9),V(13),V(13), V(9), V(9), V(1),
-    V(2), V(8),V(21),V(24),V(24),V(21), V(8), V(2),
-    V(0), V(4), V(6), V(6), V(6), V(6), V(4), V(0) }
+  // Outpost[knight/bishop][supported by pawn] contains bonuses for knights and bishops
+  // outposts, bigger if outpost piece is supported by a pawn.
+  const Score Outpost[][2] = {
+    { S(28, 7), S(42,11) }, // Knights
+    { S(12, 3), S(18, 5) }  // Bishops
   };
 
   // Threat[defended/weak][minor/major attacking][attacked PieceType] contains
@@ -235,33 +223,6 @@ namespace {
   }
 
 
-  // evaluate_outpost() evaluates bishop and knight outpost squares
-
-  template<PieceType Pt, Color Us>
-  Score evaluate_outpost(const Position& pos, const EvalInfo& ei, Square s) {
-
-    const Color Them = (Us == WHITE ? BLACK : WHITE);
-
-    assert (Pt == BISHOP || Pt == KNIGHT);
-
-    // Initial bonus based on square
-    Value bonus = Outpost[Pt == BISHOP][relative_square(Us, s)];
-
-    // Increase bonus if supported by pawn, especially if the opponent has
-    // no minor piece which can trade with the outpost piece.
-    if (bonus && (ei.attackedBy[Us][PAWN] & s))
-    {
-        if (   !pos.pieces(Them, KNIGHT)
-            && !(squares_of_color(s) & pos.pieces(Them, BISHOP)))
-            bonus += bonus + bonus / 2;
-        else
-            bonus += bonus / 2;
-    }
-
-    return make_score(bonus * 2, bonus / 2);
-  }
-
-
   // evaluate_pieces() assigns bonuses and penalties to the pieces of a given color
 
   template<PieceType Pt, Color Us, bool Trace>
@@ -310,8 +271,9 @@ namespace {
         if (Pt == BISHOP || Pt == KNIGHT)
         {
             // Bonus for outpost square
-            if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
-                score += evaluate_outpost<Pt, Us>(pos, ei, s);
+            if (   relative_rank(Us, s) >= RANK_4
+                && !(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
+                score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)];
 
             // Bonus when behind a pawn
             if (    relative_rank(Us, s) < RANK_5
@@ -739,9 +701,18 @@ namespace {
     ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING];
     ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING];
 
-    // Do not include in mobility squares protected by enemy pawns or occupied by our pawns or king
-    Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)),
-                                ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) };
+    // Pawns blocked or on ranks 2 and 3. Will be excluded from the mobility area
+    Bitboard blockedPawns[] = {
+      pos.pieces(WHITE, PAWN) & (shift_bb<DELTA_S>(pos.pieces()) | Rank2BB | Rank3BB),
+      pos.pieces(BLACK, PAWN) & (shift_bb<DELTA_N>(pos.pieces()) | Rank7BB | Rank6BB)
+    };
+
+    // Do not include in mobility squares protected by enemy pawns, or occupied
+    // by our blocked pawns or king.
+    Bitboard mobilityArea[] = {
+      ~(ei.attackedBy[BLACK][PAWN] | blockedPawns[WHITE] | pos.king_square(WHITE)),
+      ~(ei.attackedBy[WHITE][PAWN] | blockedPawns[BLACK] | pos.king_square(BLACK))
+    };
 
     // Evaluate pieces and mobility
     score += evaluate_pieces<KNIGHT, WHITE, Trace>(pos, ei, mobility, mobilityArea);