Use templates for end game evaluation functions

Huge simplification and no speed cost penalty.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/endgame.cpp b/src/endgame.cpp
index 9fafb042d86452f56006f23732f64c7b51bd436f..f01f75a0171ff2df2b41f888e489531b5d65aef0 100644 (file)
--- a/src/endgame.cpp
+++ b/src/endgame.cpp
@@ -35,39 +35,18 @@
 /// Evaluation functions
 
 // Generic "mate lone king" eval
-KXKEvaluationFunction EvaluateKXK = KXKEvaluationFunction(WHITE);
-KXKEvaluationFunction EvaluateKKX = KXKEvaluationFunction(BLACK);
-
-// KBN vs K
-KBNKEvaluationFunction EvaluateKBNK = KBNKEvaluationFunction(WHITE);
-KBNKEvaluationFunction EvaluateKKBN = KBNKEvaluationFunction(BLACK);
-
-// KP vs K
-KPKEvaluationFunction EvaluateKPK = KPKEvaluationFunction(WHITE);
-KPKEvaluationFunction EvaluateKKP = KPKEvaluationFunction(BLACK);
-
-// KR vs KP
-KRKPEvaluationFunction EvaluateKRKP = KRKPEvaluationFunction(WHITE);
-KRKPEvaluationFunction EvaluateKPKR = KRKPEvaluationFunction(BLACK);
-
-// KR vs KB
-KRKBEvaluationFunction EvaluateKRKB = KRKBEvaluationFunction(WHITE);
-KRKBEvaluationFunction EvaluateKBKR = KRKBEvaluationFunction(BLACK);
-
-// KR vs KN
-KRKNEvaluationFunction EvaluateKRKN = KRKNEvaluationFunction(WHITE);
-KRKNEvaluationFunction EvaluateKNKR = KRKNEvaluationFunction(BLACK);
-
-// KQ vs KR
-KQKREvaluationFunction EvaluateKQKR = KQKREvaluationFunction(WHITE);
-KQKREvaluationFunction EvaluateKRKQ = KQKREvaluationFunction(BLACK);
-
-// KBB vs KN
-KBBKNEvaluationFunction EvaluateKBBKN = KBBKNEvaluationFunction(WHITE);
-KBBKNEvaluationFunction EvaluateKNKBB = KBBKNEvaluationFunction(BLACK);
+EvaluationFunction<KXK> EvaluateKXK(WHITE), EvaluateKKX(BLACK);
 
 // K and two minors vs K and one or two minors
-KmmKmEvaluationFunction EvaluateKmmKm = KmmKmEvaluationFunction(WHITE);
+EvaluationFunction<KmmKm> EvaluateKmmKm(WHITE);
+
+EvaluationFunction<KBNK> EvaluateKBNK(WHITE), EvaluateKKBN(BLACK); // KBN vs K
+EvaluationFunction<KPK> EvaluateKPK(WHITE), EvaluateKKP(BLACK);    // KP vs K
+EvaluationFunction<KRKP> EvaluateKRKP(WHITE), EvaluateKPKR(BLACK); // KR vs KP
+EvaluationFunction<KRKB> EvaluateKRKB(WHITE), EvaluateKBKR(BLACK); // KR vs KB
+EvaluationFunction<KRKN> EvaluateKRKN(WHITE), EvaluateKNKR(BLACK); // KR vs KN
+EvaluationFunction<KQKR> EvaluateKQKR(WHITE), EvaluateKRKQ(BLACK); // KQ vs KR
+EvaluationFunction<KBBKN> EvaluateKBBKN(WHITE), EvaluateKNKBB(BLACK); // KBB vs KN
 
 
 /// Scaling functions
@@ -185,17 +164,6 @@ EndgameEvaluationFunction::EndgameEvaluationFunction(Color c) : strongerSide(c)
   weakerSide = opposite_color(strongerSide);
 }
 
-KXKEvaluationFunction::KXKEvaluationFunction(Color c)     : EndgameEvaluationFunction(c) {}
-KBNKEvaluationFunction::KBNKEvaluationFunction(Color c)   : EndgameEvaluationFunction(c) {}
-KPKEvaluationFunction::KPKEvaluationFunction(Color c)     : EndgameEvaluationFunction(c) {}
-KRKPEvaluationFunction::KRKPEvaluationFunction(Color c)   : EndgameEvaluationFunction(c) {}
-KRKBEvaluationFunction::KRKBEvaluationFunction(Color c)   : EndgameEvaluationFunction(c) {}
-KRKNEvaluationFunction::KRKNEvaluationFunction(Color c)   : EndgameEvaluationFunction(c) {}
-KQKREvaluationFunction::KQKREvaluationFunction(Color c)   : EndgameEvaluationFunction(c) {}
-KBBKNEvaluationFunction::KBBKNEvaluationFunction(Color c) : EndgameEvaluationFunction(c) {}
-KmmKmEvaluationFunction::KmmKmEvaluationFunction(Color c) : EndgameEvaluationFunction(c) {}
-
-
 ScalingFunction::ScalingFunction(Color c) : strongerSide(c) {
   weakerSide = opposite_color(c);
 }
@@ -215,8 +183,8 @@ KPKPScalingFunction::KPKPScalingFunction(Color c)       : ScalingFunction(c) {}
 /// King and plenty of material vs a lone king. It simply gives the
 /// attacking side a bonus for driving the defending king towards the edge
 /// of the board, and for keeping the distance between the two kings small.
-
-Value KXKEvaluationFunction::apply(const Position& pos) {
+template<>
+Value EvaluationFunction<KXK>::apply(const Position& pos) {
 
   assert(pos.non_pawn_material(weakerSide) == Value(0));
   assert(pos.piece_count(weakerSide, PAWN) == Value(0));
@@ -241,8 +209,8 @@ Value KXKEvaluationFunction::apply(const Position& pos) {
 
 /// Mate with KBN vs K. This is similar to KX vs K, but we have to drive the
 /// defending king towards a corner square of the right color.
-
-Value KBNKEvaluationFunction::apply(const Position& pos) {
+template<>
+Value EvaluationFunction<KBNK>::apply(const Position& pos) {
 
   assert(pos.non_pawn_material(weakerSide) == Value(0));
   assert(pos.piece_count(weakerSide, PAWN) == Value(0));
@@ -270,8 +238,8 @@ Value KBNKEvaluationFunction::apply(const Position& pos) {
 
 
 /// KP vs K. This endgame is evaluated with the help of a bitbase.
-
-Value KPKEvaluationFunction::apply(const Position& pos) {
+template<>
+Value EvaluationFunction<KPK>::apply(const Position& pos) {
 
   assert(pos.non_pawn_material(strongerSide) == Value(0));
   assert(pos.non_pawn_material(weakerSide) == Value(0));
@@ -318,8 +286,8 @@ Value KPKEvaluationFunction::apply(const Position& pos) {
 /// a bitbase. The function below returns drawish scores when the pawn is
 /// far advanced with support of the king, while the attacking king is far
 /// away.
-
-Value KRKPEvaluationFunction::apply(const Position& pos) {
+template<>
+Value EvaluationFunction<KRKP>::apply(const Position& pos) {
 
   assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
   assert(pos.piece_count(strongerSide, PAWN) == 0);
@@ -375,8 +343,8 @@ Value KRKPEvaluationFunction::apply(const Position& pos) {
 
 /// KR vs KB. This is very simple, and always returns drawish scores.  The
 /// score is slightly bigger when the defending king is close to the edge.
-
-Value KRKBEvaluationFunction::apply(const Position& pos) {
+template<>
+Value EvaluationFunction<KRKB>::apply(const Position& pos) {
 
   assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
   assert(pos.piece_count(strongerSide, PAWN) == 0);
@@ -391,8 +359,8 @@ Value KRKBEvaluationFunction::apply(const Position& pos) {
 
 /// KR vs KN.  The attacking side has slightly better winning chances than
 /// in KR vs KB, particularly if the king and the knight are far apart.
-
-Value KRKNEvaluationFunction::apply(const Position& pos) {
+template<>
+Value EvaluationFunction<KRKN>::apply(const Position& pos) {
 
   assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
   assert(pos.piece_count(strongerSide, PAWN) == 0);
@@ -415,8 +383,8 @@ Value KRKNEvaluationFunction::apply(const Position& pos) {
 /// defending king towards the edge.  If we also take care to avoid null move
 /// for the defending side in the search, this is usually sufficient to be
 /// able to win KQ vs KR.
-
-Value KQKREvaluationFunction::apply(const Position& pos) {
+template<>
+Value EvaluationFunction<KQKR>::apply(const Position& pos) {
 
   assert(pos.non_pawn_material(strongerSide) == QueenValueMidgame);
   assert(pos.piece_count(strongerSide, PAWN) == 0);
@@ -434,8 +402,8 @@ Value KQKREvaluationFunction::apply(const Position& pos) {
   return (strongerSide == pos.side_to_move())? result : -result;
 }
 
-
-Value KBBKNEvaluationFunction::apply(const Position& pos) {
+template<>
+Value EvaluationFunction<KBBKN>::apply(const Position& pos) {
 
   assert(pos.piece_count(strongerSide, BISHOP) == 2);
   assert(pos.non_pawn_material(strongerSide) == 2*BishopValueMidgame);
@@ -460,8 +428,8 @@ Value KBBKNEvaluationFunction::apply(const Position& pos) {
   return (strongerSide == pos.side_to_move() ? result : -result);
 }
 
-
-Value KmmKmEvaluationFunction::apply(const Position &pos) {
+template<>
+Value EvaluationFunction<KmmKm>::apply(const Position &pos) {
   return Value(0);
 }
 

diff --git a/src/endgame.h b/src/endgame.h
index f2990e744d19a97ae19c2fa48f592f3afd360e0b..21e8ab6d6e5b6d249a765f0c4381c9cf7465f93a 100644 (file)
--- a/src/endgame.h
+++ b/src/endgame.h
@@ -34,86 +34,41 @@
 //// Types
 ////
 
-/// Abstract base class for all special endgame evaluation functions:
+/// Abstract base class for all special endgame evaluation functions
 
 class EndgameEvaluationFunction {
 public:
   EndgameEvaluationFunction(Color c);
   virtual ~EndgameEvaluationFunction() { }
 
-  virtual Value apply(const Position &pos) =0;
+  virtual Value apply(const Position &pos) = 0;
 
 protected:
   Color strongerSide, weakerSide;
 };
 
 
-/// Subclasses for various concrete endgames:
-
-// Generic "mate lone king" eval:
-class KXKEvaluationFunction : public EndgameEvaluationFunction {
-public:
-  KXKEvaluationFunction(Color c);
-  Value apply(const Position &pos);
-};
-
-// KBN vs K:
-class KBNKEvaluationFunction : public EndgameEvaluationFunction {
-public:
-  KBNKEvaluationFunction(Color c);
-  Value apply(const Position &pos);
-};
-
-// KP vs K:
-class KPKEvaluationFunction : public EndgameEvaluationFunction {
-public:
-  KPKEvaluationFunction(Color c);
-  Value apply(const Position &pos);
-};
-
-// KR vs KP:
-class KRKPEvaluationFunction : public EndgameEvaluationFunction {
-public:
-  KRKPEvaluationFunction(Color c);
-  Value apply(const Position &pos);
-};
-
-// KR vs KB:
-class KRKBEvaluationFunction : public EndgameEvaluationFunction {
-public:
-  KRKBEvaluationFunction(Color c);
-  Value apply(const Position &pos);
-};
+/// Template subclass for various concrete endgames
 
-// KR vs KN:
-class KRKNEvaluationFunction : public EndgameEvaluationFunction {
-public:
-  KRKNEvaluationFunction(Color c);
-  Value apply(const Position &pos);
-};
-
-// KQ vs KR:
-class KQKREvaluationFunction : public EndgameEvaluationFunction {
-public:
-  KQKREvaluationFunction(Color c);
-  Value apply(const Position &pos);
+enum EndgameType {
+    KXK,   // Generic "mate lone king" eval
+    KBNK,  // KBN vs K
+    KPK,   // KP vs K
+    KRKP,  // KR vs KP
+    KRKB,  // KR vs KB
+    KRKN,  // KR vs KN
+    KQKR,  // KQ vs KR
+    KBBKN, // KBB vs KN
+    KmmKm  // K and two minors vs K and one or two minors
 };
 
-// KBB vs KN:
-class KBBKNEvaluationFunction : public EndgameEvaluationFunction {
+template<EndgameType>
+class EvaluationFunction : public EndgameEvaluationFunction {
 public:
-  KBBKNEvaluationFunction(Color C);
-  Value apply(const Position &pos);
+  explicit EvaluationFunction(Color c): EndgameEvaluationFunction(c) {}
+  Value apply(const Position& pos);
 };
 
-// K and two minors vs K and one or two minors:
-class KmmKmEvaluationFunction : public EndgameEvaluationFunction {
-public:
-  KmmKmEvaluationFunction(Color c);
-  Value apply(const Position &pos);
-};
-
-
 /// Abstract base class for all evaluation scaling functions:
 
 class ScalingFunction {
@@ -198,32 +153,15 @@ public:
 //// Constants and variables
 ////
 
-// Generic "mate lone king" eval:
-extern KXKEvaluationFunction EvaluateKXK, EvaluateKKX;
-
-// KBN vs K:
-extern KBNKEvaluationFunction EvaluateKBNK, EvaluateKKBN;
-
-// KP vs K:
-extern KPKEvaluationFunction EvaluateKPK, EvaluateKKP;
-
-// KR vs KP:
-extern KRKPEvaluationFunction EvaluateKRKP, EvaluateKPKR;
-
-// KR vs KB:
-extern KRKBEvaluationFunction EvaluateKRKB, EvaluateKBKR;
-
-// KR vs KN:
-extern KRKNEvaluationFunction EvaluateKRKN, EvaluateKNKR;
-
-// KQ vs KR:
-extern KQKREvaluationFunction EvaluateKQKR, EvaluateKRKQ;
-
-// KBB vs KN:
-extern KBBKNEvaluationFunction EvaluateKBBKN, EvaluateKNKBB;
-
-// K and two minors vs K and one or two minors:
-extern KmmKmEvaluationFunction EvaluateKmmKm;
+extern EvaluationFunction<KXK> EvaluateKXK, EvaluateKKX;       // Generic "mate lone king" eval
+extern EvaluationFunction<KBNK> EvaluateKBNK, EvaluateKKBN;    // KBN vs K
+extern EvaluationFunction<KPK> EvaluateKPK, EvaluateKKP;       // KP vs K
+extern EvaluationFunction<KRKP> EvaluateKRKP, EvaluateKPKR;    // KR vs KP
+extern EvaluationFunction<KRKB> EvaluateKRKB, EvaluateKBKR;    // KR vs KB
+extern EvaluationFunction<KRKN> EvaluateKRKN, EvaluateKNKR;    // KR vs KN
+extern EvaluationFunction<KQKR> EvaluateKQKR, EvaluateKRKQ;    // KQ vs KR
+extern EvaluationFunction<KBBKN> EvaluateKBBKN, EvaluateKNKBB; // KBB vs KN
+extern EvaluationFunction<KmmKm> EvaluateKmmKm; // K and two minors vs K and one or two minors:
 
 // KBP vs K:
 extern KBPKScalingFunction ScaleKBPK, ScaleKKBP;