#include "endgame.h"
#include "pawns.h"
-extern int probe_kpk_bitbase(Square wksq, Square wpsq, Square bksq, Color stm);
+using std::string;
+
+extern uint32_t probe_kpk_bitbase(Square wksq, Square wpsq, Square bksq, Color stm);
namespace {
// Table used to drive the defending king towards the edge of the board
// in KX vs K and KQ vs KR endgames.
- const uint8_t MateTable[64] = {
+ const int MateTable[64] = {
100, 90, 80, 70, 70, 80, 90, 100,
90, 70, 60, 50, 50, 60, 70, 90,
80, 60, 40, 30, 30, 40, 60, 80,
// Table used to drive the defending king towards a corner square of the
// right color in KBN vs K endgames.
- const uint8_t KBNKMateTable[64] = {
+ const int KBNKMateTable[64] = {
200, 190, 180, 170, 160, 150, 140, 130,
190, 180, 170, 160, 150, 140, 130, 140,
180, 170, 155, 140, 140, 125, 140, 150,
// and knight in KR vs KN endgames.
const int KRKNKingKnightDistancePenalty[8] = { 0, 0, 4, 10, 20, 32, 48, 70 };
- // Various inline functions for accessing the above arrays
- inline Value mate_table(Square s) {
- return Value(MateTable[s]);
- }
+ // Build corresponding key code for the opposite color: "KBPKN" -> "KNKBP"
+ const string swap_colors(const string& keyCode) {
- inline Value kbnk_mate_table(Square s) {
- return Value(KBNKMateTable[s]);
+ size_t idx = keyCode.find('K', 1);
+ return keyCode.substr(idx) + keyCode.substr(0, idx);
}
- inline Value distance_bonus(int d) {
- return Value(DistanceBonus[d]);
- }
+ // Get the material key of a position out of the given endgame key code
+ // like "KBPKN". The trick here is to first build up a FEN string and then
+ // let a Position object to do the work for us. Note that the FEN string
+ // could correspond to an illegal position.
+ Key mat_key(const string& keyCode) {
+
+ assert(keyCode.length() > 0 && keyCode.length() < 8);
+ assert(keyCode[0] == 'K');
+
+ string fen;
+ size_t i = 0;
+
+ // First add white and then black pieces
+ do fen += keyCode[i]; while (keyCode[++i] != 'K');
+ do fen += char(tolower(keyCode[i])); while (++i < keyCode.length());
+
+ // Add file padding and remaining empty ranks
+ fen += string(1, '0' + int(8 - keyCode.length())) + "/8/8/8/8/8/8/8 w - -";
- inline Value krkn_king_knight_distance_penalty(int d) {
- return Value(KRKNKingKnightDistancePenalty[d]);
+ // Build a Position out of the fen string and get its material key
+ return Position(fen, false, 0).get_material_key();
}
+ typedef EndgameBase<Value> EF;
+ typedef EndgameBase<ScaleFactor> SF;
+
+} // namespace
+
+
+/// Endgames member definitions
+
+template<> const Endgames::EFMap& Endgames::get<EF>() const { return maps.first; }
+template<> const Endgames::SFMap& Endgames::get<SF>() const { return maps.second; }
+
+Endgames::Endgames() {
+
+ add<Endgame<Value, KNNK> >("KNNK");
+ add<Endgame<Value, KPK> >("KPK");
+ add<Endgame<Value, KBNK> >("KBNK");
+ add<Endgame<Value, KRKP> >("KRKP");
+ add<Endgame<Value, KRKB> >("KRKB");
+ add<Endgame<Value, KRKN> >("KRKN");
+ add<Endgame<Value, KQKR> >("KQKR");
+ add<Endgame<Value, KBBKN> >("KBBKN");
+
+ add<Endgame<ScaleFactor, KNPK> >("KNPK");
+ add<Endgame<ScaleFactor, KRPKR> >("KRPKR");
+ add<Endgame<ScaleFactor, KBPKB> >("KBPKB");
+ add<Endgame<ScaleFactor, KBPPKB> >("KBPPKB");
+ add<Endgame<ScaleFactor, KBPKN> >("KBPKN");
+ add<Endgame<ScaleFactor, KRPPKRP> >("KRPPKRP");
}
+Endgames::~Endgames() {
+
+ for (EFMap::const_iterator it = get<EF>().begin(); it != get<EF>().end(); ++it)
+ delete it->second;
+
+ for (SFMap::const_iterator it = get<SF>().begin(); it != get<SF>().end(); ++it)
+ delete it->second;
+}
+
+template<class T>
+void Endgames::add(const string& keyCode) {
+
+ typedef typename T::Base F;
+ typedef std::map<Key, F*> M;
+
+ const_cast<M&>(get<F>()).insert(std::pair<Key, F*>(mat_key(keyCode), new T(WHITE)));
+ const_cast<M&>(get<F>()).insert(std::pair<Key, F*>(mat_key(swap_colors(keyCode)), new T(BLACK)));
+}
+
+template<class T>
+T* Endgames::get(Key key) const {
+
+ typename std::map<Key, T*>::const_iterator it = get<T>().find(key);
+ return it != get<T>().end() ? it->second : NULL;
+}
+
+// Explicit template instantiations
+template EF* Endgames::get<EF>(Key key) const;
+template SF* Endgames::get<SF>(Key key) const;
+
/// Mate with KX vs K. This function is used to evaluate positions with
/// 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.
template<>
-Value EvaluationFunction<KXK>::apply(const Position& pos) const {
+Value Endgame<Value, KXK>::apply(const Position& pos) const {
assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
assert(pos.piece_count(weakerSide, PAWN) == VALUE_ZERO);
Value result = pos.non_pawn_material(strongerSide)
+ pos.piece_count(strongerSide, PAWN) * PawnValueEndgame
- + mate_table(loserKSq)
- + distance_bonus(square_distance(winnerKSq, loserKSq));
+ + MateTable[loserKSq]
+ + DistanceBonus[square_distance(winnerKSq, loserKSq)];
if ( pos.piece_count(strongerSide, QUEEN)
|| pos.piece_count(strongerSide, ROOK)
/// 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.
template<>
-Value EvaluationFunction<KBNK>::apply(const Position& pos) const {
+Value Endgame<Value, KBNK>::apply(const Position& pos) const {
assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
assert(pos.piece_count(weakerSide, PAWN) == VALUE_ZERO);
}
Value result = VALUE_KNOWN_WIN
- + distance_bonus(square_distance(winnerKSq, loserKSq))
- + kbnk_mate_table(loserKSq);
+ + DistanceBonus[square_distance(winnerKSq, loserKSq)]
+ + KBNKMateTable[loserKSq];
return strongerSide == pos.side_to_move() ? result : -result;
}
/// KP vs K. This endgame is evaluated with the help of a bitbase.
template<>
-Value EvaluationFunction<KPK>::apply(const Position& pos) const {
+Value Endgame<Value, KPK>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);
/// far advanced with support of the king, while the attacking king is far
/// away.
template<>
-Value EvaluationFunction<KRKP>::apply(const Position& pos) const {
+Value Endgame<Value, KRKP>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
assert(pos.piece_count(strongerSide, PAWN) == 0);
/// 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.
template<>
-Value EvaluationFunction<KRKB>::apply(const Position& pos) const {
+Value Endgame<Value, KRKB>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
assert(pos.piece_count(strongerSide, PAWN) == 0);
assert(pos.piece_count(weakerSide, PAWN) == 0);
assert(pos.piece_count(weakerSide, BISHOP) == 1);
- Value result = mate_table(pos.king_square(weakerSide));
+ Value result = Value(MateTable[pos.king_square(weakerSide)]);
return strongerSide == pos.side_to_move() ? result : -result;
}
/// 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.
template<>
-Value EvaluationFunction<KRKN>::apply(const Position& pos) const {
+Value Endgame<Value, KRKN>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
assert(pos.piece_count(strongerSide, PAWN) == 0);
int d = square_distance(defendingKSq, nSq);
Value result = Value(10)
- + mate_table(defendingKSq)
- + krkn_king_knight_distance_penalty(d);
+ + MateTable[defendingKSq]
+ + KRKNKingKnightDistancePenalty[d];
return strongerSide == pos.side_to_move() ? result : -result;
}
/// for the defending side in the search, this is usually sufficient to be
/// able to win KQ vs KR.
template<>
-Value EvaluationFunction<KQKR>::apply(const Position& pos) const {
+Value Endgame<Value, KQKR>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == QueenValueMidgame);
assert(pos.piece_count(strongerSide, PAWN) == 0);
Value result = QueenValueEndgame
- RookValueEndgame
- + mate_table(loserKSq)
- + distance_bonus(square_distance(winnerKSq, loserKSq));
+ + MateTable[loserKSq]
+ + DistanceBonus[square_distance(winnerKSq, loserKSq)];
return strongerSide == pos.side_to_move() ? result : -result;
}
template<>
-Value EvaluationFunction<KBBKN>::apply(const Position& pos) const {
+Value Endgame<Value, KBBKN>::apply(const Position& pos) const {
assert(pos.piece_count(strongerSide, BISHOP) == 2);
assert(pos.non_pawn_material(strongerSide) == 2*BishopValueMidgame);
Square nsq = pos.piece_list(weakerSide, KNIGHT, 0);
// Bonus for attacking king close to defending king
- result += distance_bonus(square_distance(wksq, bksq));
+ result += Value(DistanceBonus[square_distance(wksq, bksq)]);
// Bonus for driving the defending king and knight apart
result += Value(square_distance(bksq, nsq) * 32);
/// K and two minors vs K and one or two minors or K and two knights against
/// king alone are always draw.
template<>
-Value EvaluationFunction<KmmKm>::apply(const Position&) const {
+Value Endgame<Value, KmmKm>::apply(const Position&) const {
return VALUE_DRAW;
}
template<>
-Value EvaluationFunction<KNNK>::apply(const Position&) const {
+Value Endgame<Value, KNNK>::apply(const Position&) const {
return VALUE_DRAW;
}
/// returned. If not, the return value is SCALE_FACTOR_NONE, i.e. no scaling
/// will be used.
template<>
-ScaleFactor ScalingFunction<KBPsK>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KBPsK>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
assert(pos.piece_count(strongerSide, BISHOP) == 1);
/// It tests for fortress draws with a rook on the third rank defended by
/// a pawn.
template<>
-ScaleFactor ScalingFunction<KQKRPs>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KQKRPs>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == QueenValueMidgame);
assert(pos.piece_count(strongerSide, QUEEN) == 1);
/// It would also be nice to rewrite the actual code for this function,
/// which is mostly copied from Glaurung 1.x, and not very pretty.
template<>
-ScaleFactor ScalingFunction<KRPKR>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KRPKR>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
assert(pos.piece_count(strongerSide, PAWN) == 1);
/// single pattern: If the stronger side has no pawns and the defending king
/// is actively placed, the position is drawish.
template<>
-ScaleFactor ScalingFunction<KRPPKRP>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KRPPKRP>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
assert(pos.piece_count(strongerSide, PAWN) == 2);
/// against king. There is just a single rule here: If all pawns are on
/// the same rook file and are blocked by the defending king, it's a draw.
template<>
-ScaleFactor ScalingFunction<KPsK>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KPsK>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
assert(pos.piece_count(strongerSide, PAWN) >= 2);
/// it's a draw. If the two bishops have opposite color, it's almost always
/// a draw.
template<>
-ScaleFactor ScalingFunction<KBPKB>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KBPKB>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
assert(pos.piece_count(strongerSide, BISHOP) == 1);
/// KBPPKBScalingFunction scales KBPP vs KB endgames. It detects a few basic
/// draws with opposite-colored bishops.
template<>
-ScaleFactor ScalingFunction<KBPPKB>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KBPPKB>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
assert(pos.piece_count(strongerSide, BISHOP) == 1);
/// square of the king is not of the same color as the stronger side's bishop,
/// it's a draw.
template<>
-ScaleFactor ScalingFunction<KBPKN>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KBPKN>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
assert(pos.piece_count(strongerSide, BISHOP) == 1);
/// If the pawn is a rook pawn on the 7th rank and the defending king prevents
/// the pawn from advancing, the position is drawn.
template<>
-ScaleFactor ScalingFunction<KNPK>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KNPK>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == KnightValueMidgame);
assert(pos.piece_count(strongerSide, KNIGHT) == 1);
/// advanced and not on a rook file; in this case it is often possible to win
/// (e.g. 8/4k3/3p4/3P4/6K1/8/8/8 w - - 0 1).
template<>
-ScaleFactor ScalingFunction<KPKP>::apply(const Position& pos) const {
+ScaleFactor Endgame<ScaleFactor, KPKP>::apply(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == VALUE_ZERO);
assert(pos.non_pawn_material(weakerSide) == VALUE_ZERO);