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Call apply_weight() for both colors in one go

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Due to rounding errors in apply_weight() where we divide
by 0x100 it is not possible to keep some functionality.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2010-06-05 18:05:29 +01:00
parent 74db0f0f40
commit 6776f76d20
1 changed files with 13 additions and 16 deletions
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29
src/evaluate.cpp
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@ -255,7 +255,7 @@ namespace {
void evaluate_threats(const Position& pos, EvalInfo& ei);
template<Color Us, bool HasPopCnt>
void evaluate_space(const Position& pos, EvalInfo& ei);
int evaluate_space(const Position& pos, EvalInfo& ei);
template<Color Us>
void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
@ -362,8 +362,8 @@ Value do_evaluate(const Position& pos, EvalInfo& ei) {
// Evaluate space for both sides
if (ei.mi->space_weight() > 0)
{
evaluate_space<WHITE, HasPopCnt>(pos, ei);
evaluate_space<BLACK, HasPopCnt>(pos, ei);
int s = evaluate_space<WHITE, HasPopCnt>(pos, ei) - evaluate_space<BLACK, HasPopCnt>(pos, ei);
ei.value += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
}
}
@ -470,7 +470,7 @@ void read_weights(Color us) {
namespace {
// init_king_tables() initializes king bitboards for both sides adding
// init_attack_tables() initializes king bitboards for both sides adding
// pawn attacks. To be done before other evaluations.
template<Color Us, bool HasPopCnt>
@ -1039,27 +1039,24 @@ namespace {
// twice. Finally, the space bonus is scaled by a weight taken from the
// material hash table.
template<Color Us, bool HasPopCnt>
void evaluate_space(const Position& pos, EvalInfo& ei) {
int evaluate_space(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
// Find the safe squares for our pieces inside the area defined by
// SpaceMask[us]. A square is unsafe if it is attacked by an enemy
// pawn, or if it is undefended and attacked by an enemy piece.
Bitboard safeSquares = SpaceMask[Us]
& ~pos.pieces(PAWN, Us)
& ~ei.attacked_by(Them, PAWN)
& (ei.attacked_by(Us) | ~ei.attacked_by(Them));
Bitboard safe = SpaceMask[Us]
& ~pos.pieces(PAWN, Us)
& ~ei.attacked_by(Them, PAWN)
& (ei.attacked_by(Us) | ~ei.attacked_by(Them));
// Find all squares which are at most three squares behind some friendly pawn
Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us);
behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8);
behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16);
Bitboard behind = pos.pieces(PAWN, Us);
behind |= (Us == WHITE ? behind >> 8 : behind << 8);
behind |= (Us == WHITE ? behind >> 16 : behind << 16);
int space = count_1s_max_15<HasPopCnt>(safeSquares)
+ count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), Weights[Space]);
return count_1s_max_15<HasPopCnt>(safe) + count_1s_max_15<HasPopCnt>(behind & safe);
}