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DroidFish: Updated stockfish engine to version 3.

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Peter Osterlund
2013-05-03 17:03:42 +00:00
parent 3f55b61865
commit 34b9fd139f
42 changed files with 2092 additions and 2383 deletions
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100
DroidFish/jni/stockfish/endgame.cpp
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@@ -1,7 +1,7 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@@ -31,7 +31,7 @@ namespace {
// Table used to drive the defending king towards the edge of the board
// in KX vs K and KQ vs KR endgames.
const int MateTable[64] = {
const int MateTable[SQUARE_NB] = {
100, 90, 80, 70, 70, 80, 90, 100,
90, 70, 60, 50, 50, 60, 70, 90,
80, 60, 40, 30, 30, 40, 60, 80,
@@ -44,7 +44,7 @@ namespace {
// Table used to drive the defending king towards a corner square of the
// right color in KBN vs K endgames.
const int KBNKMateTable[64] = {
const int KBNKMateTable[SQUARE_NB] = {
200, 190, 180, 170, 160, 150, 140, 130,
190, 180, 170, 160, 150, 140, 130, 140,
180, 170, 155, 140, 140, 125, 140, 150,
@@ -95,10 +95,12 @@ Endgames::Endgames() {
add<KRKP>("KRKP");
add<KRKB>("KRKB");
add<KRKN>("KRKN");
add<KQKP>("KQKP");
add<KQKR>("KQKR");
add<KBBKN>("KBBKN");
add<KNPK>("KNPK");
add<KNPKB>("KNPKB");
add<KRPKR>("KRPKR");
add<KBPKB>("KBPKB");
add<KBPKN>("KBPKN");
@@ -132,7 +134,7 @@ Value Endgame<KXK>::operator()(const Position& pos) const {
// Stalemate detection with lone king
if ( pos.side_to_move() == weakerSide
&& !pos.in_check()
&& !pos.checkers()
&& !MoveList<LEGAL>(pos).size()) {
return VALUE_DRAW;
}
@@ -169,12 +171,12 @@ Value Endgame<KBNK>::operator()(const Position& pos) const {
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
Square bishopSquare = pos.piece_list(strongerSide, BISHOP)[0];
Square bishopSq = pos.piece_list(strongerSide, BISHOP)[0];
// kbnk_mate_table() tries to drive toward corners A1 or H8,
// if we have a bishop that cannot reach the above squares we
// mirror the kings so to drive enemy toward corners A8 or H1.
if (opposite_colors(bishopSquare, SQ_A1))
if (opposite_colors(bishopSq, SQ_A1))
{
winnerKSq = mirror(winnerKSq);
loserKSq = mirror(loserKSq);
@@ -198,21 +200,21 @@ Value Endgame<KPK>::operator()(const Position& pos) const {
assert(pos.piece_count(weakerSide, PAWN) == 0);
Square wksq, bksq, wpsq;
Color stm;
Color us;
if (strongerSide == WHITE)
{
wksq = pos.king_square(WHITE);
bksq = pos.king_square(BLACK);
wpsq = pos.piece_list(WHITE, PAWN)[0];
stm = pos.side_to_move();
us = pos.side_to_move();
}
else
{
wksq = ~pos.king_square(BLACK);
bksq = ~pos.king_square(WHITE);
wpsq = ~pos.piece_list(BLACK, PAWN)[0];
stm = ~pos.side_to_move();
us = ~pos.side_to_move();
}
if (file_of(wpsq) >= FILE_E)
@@ -222,7 +224,7 @@ Value Endgame<KPK>::operator()(const Position& pos) const {
wpsq = mirror(wpsq);
}
if (!Bitbases::probe_kpk(wksq, wpsq, bksq, stm))
if (!Bitbases::probe_kpk(wksq, wpsq, bksq, us))
return VALUE_DRAW;
Value result = VALUE_KNOWN_WIN + PawnValueEg + Value(rank_of(wpsq));
@@ -326,6 +328,37 @@ Value Endgame<KRKN>::operator()(const Position& pos) const {
}
/// KQ vs KP. In general, a win for the stronger side, however, there are a few
/// important exceptions. Pawn on 7th rank, A,C,F or H file, with king next can
/// be a draw, so we scale down to distance between kings only.
template<>
Value Endgame<KQKP>::operator()(const Position& pos) const {
assert(pos.non_pawn_material(strongerSide) == QueenValueMg);
assert(pos.piece_count(strongerSide, PAWN) == 0);
assert(pos.non_pawn_material(weakerSide) == 0);
assert(pos.piece_count(weakerSide, PAWN) == 1);
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
Square pawnSq = pos.piece_list(weakerSide, PAWN)[0];
Value result = QueenValueEg
- PawnValueEg
+ DistanceBonus[square_distance(winnerKSq, loserKSq)];
if ( square_distance(loserKSq, pawnSq) == 1
&& relative_rank(weakerSide, pawnSq) == RANK_7)
{
File f = file_of(pawnSq);
if (f == FILE_A || f == FILE_C || f == FILE_F || f == FILE_H)
result = Value(DistanceBonus[square_distance(winnerKSq, loserKSq)]);
}
return strongerSide == pos.side_to_move() ? result : -result;
}
/// KQ vs KR. This is almost identical to KX vs K: We give the attacking
/// king a bonus for having the kings close together, and for forcing the
/// defending king towards the edge. If we also take care to avoid null move
@@ -439,6 +472,29 @@ ScaleFactor Endgame<KBPsK>::operator()(const Position& pos) const {
return SCALE_FACTOR_DRAW;
}
}
// All pawns on same B or G file? Then potential draw
if ( (pawnFile == FILE_B || pawnFile == FILE_G)
&& !(pos.pieces(PAWN) & ~file_bb(pawnFile))
&& pos.non_pawn_material(weakerSide) == 0
&& pos.piece_count(weakerSide, PAWN) >= 1)
{
// Get weaker pawn closest to opponent's queening square
Bitboard wkPawns = pos.pieces(weakerSide, PAWN);
Square weakerPawnSq = strongerSide == WHITE ? msb(wkPawns) : lsb(wkPawns);
Square strongerKingSq = pos.king_square(strongerSide);
Square weakerKingSq = pos.king_square(weakerSide);
Square bishopSq = pos.piece_list(strongerSide, BISHOP)[0];
// Draw if weaker pawn is on rank 7, bishop can't attack the pawn, and
// weaker king can stop opposing opponent's king from penetrating.
if ( relative_rank(strongerSide, weakerPawnSq) == RANK_7
&& opposite_colors(bishopSq, weakerPawnSq)
&& square_distance(weakerPawnSq, weakerKingSq) <= square_distance(weakerPawnSq, strongerKingSq))
return SCALE_FACTOR_DRAW;
}
return SCALE_FACTOR_NONE;
}
@@ -849,6 +905,24 @@ ScaleFactor Endgame<KNPK>::operator()(const Position& pos) const {
}
/// K, knight and a pawn vs K and bishop. If knight can block bishop from taking
/// pawn, it's a win. Otherwise, drawn.
template<>
ScaleFactor Endgame<KNPKB>::operator()(const Position& pos) const {
Square pawnSq = pos.piece_list(strongerSide, PAWN)[0];
Square bishopSq = pos.piece_list(weakerSide, BISHOP)[0];
Square weakerKingSq = pos.king_square(weakerSide);
// King needs to get close to promoting pawn to prevent knight from blocking.
// Rules for this are very tricky, so just approximate.
if (forward_bb(strongerSide, pawnSq) & pos.attacks_from<BISHOP>(bishopSq))
return ScaleFactor(square_distance(weakerKingSq, pawnSq));
return SCALE_FACTOR_NONE;
}
/// K and a pawn vs K and a pawn. This is done by removing the weakest side's
/// pawn and probing the KP vs K bitbase: If the weakest side has a draw without
/// the pawn, she probably has at least a draw with the pawn as well. The exception
@@ -865,14 +939,14 @@ ScaleFactor Endgame<KPKP>::operator()(const Position& pos) const {
Square wksq = pos.king_square(strongerSide);
Square bksq = pos.king_square(weakerSide);
Square wpsq = pos.piece_list(strongerSide, PAWN)[0];
Color stm = pos.side_to_move();
Color us = pos.side_to_move();
if (strongerSide == BLACK)
{
wksq = ~wksq;
bksq = ~bksq;
wpsq = ~wpsq;
stm = ~stm;
us = ~us;
}
if (file_of(wpsq) >= FILE_E)
@@ -890,5 +964,5 @@ ScaleFactor Endgame<KPKP>::operator()(const Position& pos) const {
// Probe the KPK bitbase with the weakest side's pawn removed. If it's a draw,
// it's probably at least a draw even with the pawn.
return Bitbases::probe_kpk(wksq, wpsq, bksq, stm) ? SCALE_FACTOR_NONE : SCALE_FACTOR_DRAW;
return Bitbases::probe_kpk(wksq, wpsq, bksq, us) ? SCALE_FACTOR_NONE : SCALE_FACTOR_DRAW;
}