Correct Pawn Trace Score + Code Clean up

No functional change

Resolves #542

diff --git a/src/benchmark.cpp b/src/benchmark.cpp
index 33e266898e415f5515fe9d965d13959726ade919..8eaa8824edb6bcf1e6fd5af1c150cbd7e85c242d 100644 (file)
--- a/src/benchmark.cpp
+++ b/src/benchmark.cpp
@@ -75,7 +75,7 @@ const vector<string> Defaults = {
   "8/8/3P3k/8/1p6/8/1P6/1K3n2 b - - 0 1",  // Nd2 - draw
 
   // 7-man positions
   "8/8/3P3k/8/1p6/8/1P6/1K3n2 b - - 0 1",  // Nd2 - draw
 
   // 7-man positions

-  "8/R7/2q5/8/6k1/8/1P5p/K6R w - - 0 124", // Draw
+  "8/R7/2q5/8/6k1/8/1P5p/K6R w - - 0 124"  // Draw

 };
 
 } // namespace
 };
 
 } // namespace

diff --git a/src/endgame.cpp b/src/endgame.cpp
index 681b290c4711edd8d2d08fe92dd3afcc24b67fb0..8eb767888562b45dab4c2830aebef55bd53c4420 100644 (file)
--- a/src/endgame.cpp
+++ b/src/endgame.cpp
@@ -39,7 +39,7 @@ namespace {
      70, 50, 30, 20, 20, 30, 50,  70,
      80, 60, 40, 30, 30, 40, 60,  80,
      90, 70, 60, 50, 50, 60, 70,  90,
      70, 50, 30, 20, 20, 30, 50,  70,
      80, 60, 40, 30, 30, 40, 60,  80,
      90, 70, 60, 50, 50, 60, 70,  90,

-    100, 90, 80, 70, 70, 80, 90, 100,
+    100, 90, 80, 70, 70, 80, 90, 100

   };
 
   // Table used to drive the king towards a corner square of the
   };
 
   // Table used to drive the king towards a corner square of the

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 925d70ac94216743bc0bb9bcc8653fcf89c5ac7d..3379725c2b193cbeeb519c52664aacdca83ff93f 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -111,8 +111,7 @@ namespace {
   enum { PawnStructure, PassedPawns, Space, KingSafety };
 
   const struct Weight { int mg, eg; } Weights[] = {
   enum { PawnStructure, PassedPawns, Space, KingSafety };
 
   const struct Weight { int mg, eg; } Weights[] = {

-    {214, 203}, {193, 262}, {47, 0}, {330, 0}
-  };
+    {214, 203}, {193, 262}, {47, 0}, {330, 0} };

 
   Score operator*(Score s, const Weight& w) {
     return make_score(mg_value(s) * w.mg / 256, eg_value(s) * w.eg / 256);
 
   Score operator*(Score s, const Weight& w) {
     return make_score(mg_value(s) * w.mg / 256, eg_value(s) * w.eg / 256);


@@ -156,19 +155,26 @@ namespace {
     { S( 8, 2), S(13, 4) }  // Bishops
   };
 
     { S( 8, 2), S(13, 4) }  // Bishops
   };
 

-  // Threat[minor/rook][attacked PieceType] contains
+  // RookOnFile[semiopen/open] contains bonuses for each rook when there is no
+  // friendly pawn on the rook file.
+  const Score RookOnFile[2] = { S(19, 10), S(43, 21) };
+
+  // ThreatBySafePawn[PieceType] contains bonuses according to which piece
+  // type is attacked by a pawn which is protected or not attacked.
+  const Score ThreatBySafePawn[PIECE_TYPE_NB] = {
+    S(0, 0), S(0, 0), S(176, 139), S(131, 127), S(217, 218), S(203, 215) };
+  
+  // Threat[by minor/by rook][attacked PieceType] contains

   // bonuses according to which piece type attacks which one.
   // Attacks on lesser pieces which are pawn defended are not considered.
   // bonuses according to which piece type attacks which one.
   // Attacks on lesser pieces which are pawn defended are not considered.

-  const Score Threat[2][PIECE_TYPE_NB] = {
-   { S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72, 107), S(48,118) }, // Minor attacks
-   { S(0, 0), S(0, 25), S(40, 62), S(40, 59), S( 0,  34), S(35, 48) }  // Rook attacks
+  const Score Threat[][PIECE_TYPE_NB] = {
+    { S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72,107), S(48,118) }, // by Minor
+    { S(0, 0), S(0, 25), S(40, 62), S(40, 59), S( 0, 34), S(35, 48) }  // by Rook

   };
 
   };
 

-  // ThreatenedByPawn[PieceType] contains a penalty according to which piece
-  // type is attacked by a pawn.
-  const Score ThreatenedByPawn[PIECE_TYPE_NB] = {
-    S(0, 0), S(0, 0), S(176, 139), S(131, 127), S(217, 218), S(203, 215)
-  };
+  // ThreatByKing[on one/on many] contains bonuses for King attacks on
+  // pawns or pieces which are not pawn defended.
+  const Score ThreatByKing[2] = { S(3, 62), S(9, 138) };

 
   // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns.
   // We don't use a Score because we process the two components independently.
 
   // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns.
   // We don't use a Score because we process the two components independently.


@@ -177,27 +183,22 @@ namespace {
     { V(7), V(14), V(37), V(63), V(134), V(189) }
   };
 
     { V(7), V(14), V(37), V(63), V(134), V(189) }
   };
 

-  // PassedFile[File] contains a bonus according to the file of a passed pawn.
-  const Score PassedFile[] = {
-    S( 12,  10), S( 3, 10), S( 1, -8), S(-27, -12),
-    S(-27, -12), S( 1, -8), S( 3, 10), S( 12,  10)
+  // PassedFile[File] contains a bonus according to the file of a passed pawn
+  const Score PassedFile[FILE_NB] = {
+    S( 12, 10), S( 3, 10), S( 1, -8), S(-27,-12),
+    S(-27,-12), S( 1, -8), S( 3, 10), S( 12, 10)

   };
 
   };
 

-  const Score ThreatenedByHangingPawn = S(70, 63);
-

   // Assorted bonuses and penalties used by evaluation
   // Assorted bonuses and penalties used by evaluation

-  const Score KingOnOne          = S( 3, 62);
-  const Score KingOnMany         = S( 9,138);
-  const Score RookOnPawn         = S( 7, 27);
-  const Score RookOnOpenFile     = S(43, 21);
-  const Score RookOnSemiOpenFile = S(19, 10);
-  const Score BishopPawns        = S( 8, 12);
-  const Score MinorBehindPawn    = S(16,  0);
-  const Score TrappedRook        = S(92,  0);
-  const Score Unstoppable        = S( 0, 20);
-  const Score Hanging            = S(48, 28);
-  const Score PawnAttackThreat   = S(31, 19);
-  const Score Checked            = S(20, 20);
+  const Score MinorBehindPawn     = S(16,  0);
+  const Score BishopPawns         = S( 8, 12);
+  const Score RookOnPawn          = S( 7, 27);
+  const Score TrappedRook         = S(92,  0);
+  const Score Checked             = S(20, 20);
+  const Score ThreatByHangingPawn = S(70, 63);
+  const Score Hanging             = S(48, 28);
+  const Score ThreatByPawnPush    = S(31, 19);
+  const Score Unstoppable         = S( 0, 20);

 
   // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
   // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
 
   // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
   // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only


@@ -343,15 +344,15 @@ namespace {
             {
                 Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
                 if (alignedPawns)
             {
                 Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
                 if (alignedPawns)

-                    score += popcount<Max15>(alignedPawns) * RookOnPawn;
+                    score += RookOnPawn * popcount<Max15>(alignedPawns);

             }
 
             // Bonus when on an open or semi-open file
             if (ei.pi->semiopen_file(Us, file_of(s)))
             }
 
             // Bonus when on an open or semi-open file
             if (ei.pi->semiopen_file(Us, file_of(s)))

-                score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOnOpenFile : RookOnSemiOpenFile;
+                score += RookOnFile[!!ei.pi->semiopen_file(Them, file_of(s))];

 
             // Penalize when trapped by the king, even more if king cannot castle
 
             // Penalize when trapped by the king, even more if king cannot castle

-            if (mob <= 3 && !ei.pi->semiopen_file(Us, file_of(s)))
+            else if (mob <= 3)

             {
                 Square ksq = pos.square<KING>(Us);
 
             {
                 Square ksq = pos.square<KING>(Us);
 


@@ -506,10 +507,10 @@ namespace {
         safeThreats = (shift_bb<Right>(b) | shift_bb<Left>(b)) & weak;
 
         if (weak ^ safeThreats)
         safeThreats = (shift_bb<Right>(b) | shift_bb<Left>(b)) & weak;
 
         if (weak ^ safeThreats)

-            score += ThreatenedByHangingPawn;
+            score += ThreatByHangingPawn;

 
         while (safeThreats)
 
         while (safeThreats)

-            score += ThreatenedByPawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))];
+            score += ThreatBySafePawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))];

     }
 
     // Non-pawn enemies defended by a pawn
     }
 
     // Non-pawn enemies defended by a pawn


@@ -537,7 +538,7 @@ namespace {
 
         b = weak & ei.attackedBy[Us][KING];
         if (b)
 
         b = weak & ei.attackedBy[Us][KING];
         if (b)

-            score += more_than_one(b) ? KingOnMany : KingOnOne;
+            score += ThreatByKing[more_than_one(b)];

     }
 
     // Bonus if some pawns can safely push and attack an enemy piece
     }
 
     // Bonus if some pawns can safely push and attack an enemy piece


@@ -553,7 +554,7 @@ namespace {
        & ~ei.attackedBy[Us][PAWN];
 
     if (b)
        & ~ei.attackedBy[Us][PAWN];
 
     if (b)

-        score += popcount<Max15>(b) * PawnAttackThreat;
+        score += ThreatByPawnPush * popcount<Max15>(b);

 
     if (DoTrace)
         Trace::add(THREAT, Us, score);
 
     if (DoTrace)
         Trace::add(THREAT, Us, score);


@@ -811,10 +812,10 @@ Value Eval::evaluate(const Position& pos) {
   {
       Bitboard b;
       if ((b = ei.pi->passed_pawns(WHITE)) != 0)
   {
       Bitboard b;
       if ((b = ei.pi->passed_pawns(WHITE)) != 0)

-          score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable;
+          score += Unstoppable * int(relative_rank(WHITE, frontmost_sq(WHITE, b)));

 
       if ((b = ei.pi->passed_pawns(BLACK)) != 0)
 
       if ((b = ei.pi->passed_pawns(BLACK)) != 0)

-          score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable;
+          score -= Unstoppable * int(relative_rank(BLACK, frontmost_sq(BLACK, b)));

   }
 
   // Evaluate space for both sides, only during opening
   }
 
   // Evaluate space for both sides, only during opening


@@ -839,7 +840,7 @@ Value Eval::evaluate(const Position& pos) {
   {
       Trace::add(MATERIAL, pos.psq_score());
       Trace::add(IMBALANCE, ei.me->imbalance());
   {
       Trace::add(MATERIAL, pos.psq_score());
       Trace::add(IMBALANCE, ei.me->imbalance());

-      Trace::add(PAWN, ei.pi->pawns_score());
+      Trace::add(PAWN, ei.pi->pawns_score() * Weights[PawnStructure]);

       Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
       Trace::add(SPACE, evaluate_space<WHITE>(pos, ei) * Weights[Space]
                       , evaluate_space<BLACK>(pos, ei) * Weights[Space]);
       Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
       Trace::add(SPACE, evaluate_space<WHITE>(pos, ei) * Weights[Space]
                       , evaluate_space<BLACK>(pos, ei) * Weights[Space]);

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 1653e23ad5181b01bb9a1f16c16e794faddc1a0f..626f2b57bd82958671cdbb6b2d1e9a845d255331 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -31,59 +31,60 @@ namespace {
   #define V Value
   #define S(mg, eg) make_score(mg, eg)
 
   #define V Value
   #define S(mg, eg) make_score(mg, eg)
 

-  // Doubled pawn penalty by file
-  const Score Doubled[FILE_NB] = {
-    S(13, 43), S(20, 48), S(23, 48), S(23, 48),
-    S(23, 48), S(23, 48), S(20, 48), S(13, 43) };
-

   // Isolated pawn penalty by opposed flag and file
   const Score Isolated[2][FILE_NB] = {
   // Isolated pawn penalty by opposed flag and file
   const Score Isolated[2][FILE_NB] = {

-  { S(37, 45), S(54, 52), S(60, 52), S(60, 52),
-    S(60, 52), S(60, 52), S(54, 52), S(37, 45) },
-  { S(25, 30), S(36, 35), S(40, 35), S(40, 35),
-    S(40, 35), S(40, 35), S(36, 35), S(25, 30) } };
+    { S(37, 45), S(54, 52), S(60, 52), S(60, 52),
+      S(60, 52), S(60, 52), S(54, 52), S(37, 45) },
+    { S(25, 30), S(36, 35), S(40, 35), S(40, 35),
+      S(40, 35), S(40, 35), S(36, 35), S(25, 30) } };

 
   // Backward pawn penalty by opposed flag
   const Score Backward[2] = { S(67, 42), S(49, 24) };
 
   // Backward pawn penalty by opposed flag
   const Score Backward[2] = { S(67, 42), S(49, 24) };

+  
+  // Unsupported pawn penalty, for pawns which are neither isolated or backward
+  const Score Unsupported = S(20, 10);

 
   // Connected pawn bonus by opposed, phalanx, twice supported and rank
   Score Connected[2][2][2][RANK_NB];
 
   // Connected pawn bonus by opposed, phalanx, twice supported and rank
   Score Connected[2][2][2][RANK_NB];

+  
+  // Doubled pawn penalty by file
+  const Score Doubled[FILE_NB] = {
+    S(13, 43), S(20, 48), S(23, 48), S(23, 48),
+    S(23, 48), S(23, 48), S(20, 48), S(13, 43) };

 
 

-  // Levers bonus by rank
+  // Lever bonus by rank

   const Score Lever[RANK_NB] = {
   const Score Lever[RANK_NB] = {

-    S( 0, 0), S( 0, 0), S(0, 0), S(0, 0),
-    S(20,20), S(40,40), S(0, 0), S(0, 0) };
-
-  // Unsupported pawn penalty
-  const Score UnsupportedPawnPenalty = S(20, 10);
+    S( 0,  0), S( 0,  0), S(0, 0), S(0, 0),
+    S(20, 20), S(40, 40), S(0, 0), S(0, 0) };

 
 

+  // Center bind bonus, when two pawns controls the same central square

   const Score CenterBind = S(16, 0);
 
   // Weakness of our pawn shelter in front of the king by [distance from edge][rank]
   const Value ShelterWeakness[][RANK_NB] = {
   const Score CenterBind = S(16, 0);
 
   // 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( 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) } };

 
   // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]
   const Value StormDanger[][4][RANK_NB] = {
 
   // 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( 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) } } };

 
   // Max bonus for king safety. Corresponds to start position with all the pawns
   // in front of the king and no enemy pawn on the horizon.
 
   // Max bonus for king safety. Corresponds to start position with all the pawns
   // in front of the king and no enemy pawn on the horizon.


@@ -167,7 +168,7 @@ namespace {
         assert(opposed | passed | (pawn_attack_span(Us, s) & theirPawns));
 
         // Passed pawns will be properly scored in evaluation because we need
         assert(opposed | passed | (pawn_attack_span(Us, s) & theirPawns));
 
         // Passed pawns will be properly scored in evaluation because we need

-        // full attack info to evaluate passed pawns. Only the frontmost passed
+        // full attack info to evaluate them. Only the frontmost passed

         // pawn on each file is considered a true passed pawn.
         if (passed && !doubled)
             e->passedPawns[Us] |= s;
         // pawn on each file is considered a true passed pawn.
         if (passed && !doubled)
             e->passedPawns[Us] |= s;


@@ -180,7 +181,7 @@ namespace {
             score -= Backward[opposed];
 
         else if (!supported)
             score -= Backward[opposed];
 
         else if (!supported)

-            score -= UnsupportedPawnPenalty;
+            score -= Unsupported;

 
         if (connected)
             score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
 
         if (connected)
             score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];


@@ -195,9 +196,8 @@ namespace {
     b = e->semiopenFiles[Us] ^ 0xFF;
     e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0;
 
     b = e->semiopenFiles[Us] ^ 0xFF;
     e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0;
 

-    // Center binds: Two pawns controlling the same central square

     b = shift_bb<Right>(ourPawns) & shift_bb<Left>(ourPawns) & CenterBindMask;
     b = shift_bb<Right>(ourPawns) & shift_bb<Left>(ourPawns) & CenterBindMask;

-    score += popcount<Max15>(b) * CenterBind;
+    score += CenterBind * popcount<Max15>(b);

 
     return score;
   }
 
     return score;
   }