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Move Tempo to evaluation

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Apart from the semplification it is now more clear that
the actual Tempo added was half of the indicated score.
This is becuase at start compute_psq_score() added half
Tempo unit and in do_move() white/black were respectively
adding/subtracting one Tempo unit.

Now we have directly halved Tempo constant and everything
is more clear.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2012-04-09 10:34:17 +01:00
parent 68885f78f3
commit e72b93e44f
2 changed files with 16 additions and 27 deletions
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31
src/position.cpp
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@@ -62,15 +62,8 @@ const Value PieceValueEndgame[17] = {
RookValueEndgame, QueenValueEndgame
};
namespace {
// Bonus for having the side to move (modified by Joona Kiiski)
const Score Tempo = make_score(48, 22);
// To convert a Piece to and from a FEN char
const string PieceToChar(" PNBRQK pnbrqk .");
}
// To convert a Piece to and from a FEN char
static const string PieceToChar(" PNBRQK pnbrqk .");
/// CheckInfo c'tor
@@ -934,9 +927,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
}
}
// Finish
sideToMove = ~sideToMove;
st->psqScore += (sideToMove == WHITE ? Tempo : -Tempo);
assert(pos_is_ok());
}
@@ -1127,9 +1118,7 @@ void Position::do_castle_move(Move m) {
// Update checkers BB
st->checkersBB = attackers_to(king_square(~us)) & pieces(us);
// Finish
sideToMove = ~sideToMove;
st->psqScore += (sideToMove == WHITE ? Tempo : -Tempo);
}
else
// Undo: point our state pointer back to the previous state
@@ -1172,7 +1161,6 @@ void Position::do_null_move(StateInfo& backupSt) {
st->epSquare = SQ_NONE;
st->rule50++;
st->pliesFromNull = 0;
st->psqScore += (sideToMove == WHITE ? Tempo : -Tempo);
}
assert(pos_is_ok());
@@ -1406,18 +1394,15 @@ Key Position::compute_material_key() const {
/// updated by do_move and undo_move when the program is running in debug mode.
Score Position::compute_psq_score() const {
Bitboard b;
Score result = SCORE_ZERO;
Bitboard b = pieces();
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
{
b = pieces(pt, c);
while (b)
result += pieceSquareTable[make_piece(c, pt)][pop_1st_bit(&b)];
}
while (b)
{
Square s = pop_1st_bit(&b);
result += pieceSquareTable[piece_on(s)][s];
}
result += (sideToMove == WHITE ? Tempo / 2 : -Tempo / 2);
return result;
}