These two notions are very correlated. Since connected has the most
generality, it makes sense to generalize it to encompass what is
covered by candidate.
STC:
LLR: 4.03 (-2.94,2.94) [-3.00,1.00]
Total: 11970 W: 2577 L: 2379 D: 7014
LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 13194 W: 2389 L: 2255 D: 8550
bench
7328585
- // evaluate_unstoppable_pawns() scores the most advanced among the passed and
- // candidate pawns. In case both players have no pieces but pawns, this is
- // somewhat related to the possibility that pawns are unstoppable.
+ // evaluate_unstoppable_pawns() scores the most advanced passed pawn. In case
+ // both players have no pieces but pawns, this is somewhat related to the
+ // possibility that pawns are unstoppable.
Score evaluate_unstoppable_pawns(Color us, const EvalInfo& ei) {
Score evaluate_unstoppable_pawns(Color us, const EvalInfo& ei) {
- Bitboard b = ei.pi->passed_pawns(us) | ei.pi->candidate_pawns(us);
+ Bitboard b = ei.pi->passed_pawns(us);
return b ? Unstoppable * int(relative_rank(us, frontmost_sq(us, b))) : SCORE_ZERO;
}
return b ? Unstoppable * int(relative_rank(us, frontmost_sq(us, b))) : SCORE_ZERO;
}
Position::init();
Bitbases::init_kpk();
Search::init();
Position::init();
Bitbases::init_kpk();
Search::init();
Eval::init();
Threads.init();
TT.resize(Options["Hash"]);
Eval::init();
Threads.init();
TT.resize(Options["Hash"]);
{ S(20, 28), S(29, 31), S(33, 31), S(33, 31),
S(33, 31), S(33, 31), S(29, 31), S(20, 28) } };
{ S(20, 28), S(29, 31), S(33, 31), S(33, 31),
S(33, 31), S(33, 31), S(29, 31), S(20, 28) } };
- // Connected pawn bonus by file and rank (initialized by formula)
- Score Connected[FILE_NB][RANK_NB];
-
- // Candidate passed pawn bonus by rank
- const Score CandidatePassed[RANK_NB] = {
- S( 0, 0), S( 6, 13), S(6,13), S(14,29),
- S(34,68), S(83,166), S(0, 0), S( 0, 0) };
+ // Connected bonus by rank
+ const int Connected[RANK_NB] = {0, 6, 15, 10, 57, 75, 135, 258};
// Levers bonus by rank
const Score Lever[RANK_NB] = {
// Levers bonus by rank
const Score Lever[RANK_NB] = {
Bitboard b, p, doubled;
Square s;
Bitboard b, p, doubled;
Square s;
- File f;
- bool passed, isolated, opposed, connected, backward, candidate, unsupported, lever;
+ bool passed, isolated, opposed, connected, backward, unsupported, lever;
Score value = SCORE_ZERO;
const Square* pl = pos.list<PAWN>(Us);
const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)];
Score value = SCORE_ZERO;
const Square* pl = pos.list<PAWN>(Us);
const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)];
Bitboard ourPawns = pos.pieces(Us , PAWN);
Bitboard theirPawns = pos.pieces(Them, PAWN);
Bitboard ourPawns = pos.pieces(Us , PAWN);
Bitboard theirPawns = pos.pieces(Them, PAWN);
- e->passedPawns[Us] = e->candidatePawns[Us] = 0;
+ e->passedPawns[Us] = 0;
e->kingSquares[Us] = SQ_NONE;
e->semiopenFiles[Us] = 0xFF;
e->pawnAttacks[Us] = shift_bb<Right>(ourPawns) | shift_bb<Left>(ourPawns);
e->kingSquares[Us] = SQ_NONE;
e->semiopenFiles[Us] = 0xFF;
e->pawnAttacks[Us] = shift_bb<Right>(ourPawns) | shift_bb<Left>(ourPawns);
{
assert(pos.piece_on(s) == make_piece(Us, PAWN));
{
assert(pos.piece_on(s) == make_piece(Us, PAWN));
+ Rank r = rank_of(s), rr = relative_rank(Us, s);
+ File f = file_of(s);
// This file cannot be semi-open
e->semiopenFiles[Us] &= ~(1 << f);
// This file cannot be semi-open
e->semiopenFiles[Us] &= ~(1 << f);
assert(opposed | passed | (pawn_attack_span(Us, s) & theirPawns));
assert(opposed | passed | (pawn_attack_span(Us, s) & theirPawns));
- // A not-passed pawn is a candidate to become passed, if it is free to
- // advance and if the number of friendly pawns beside or behind this
- // pawn on adjacent files is higher than or equal to the number of
- // enemy pawns in the forward direction on the adjacent files.
- candidate = !(opposed | passed | backward | isolated)
- && (b = pawn_attack_span(Them, s + pawn_push(Us)) & ourPawns) != 0
- && popcount<Max15>(b) >= popcount<Max15>(pawn_attack_span(Us, s) & theirPawns);
-
// Passed pawns will be properly scored in evaluation because we need
// full attack info to evaluate passed pawns. Only the frontmost passed
// pawn on each file is considered a true passed pawn.
// Passed pawns will be properly scored in evaluation because we need
// full attack info to evaluate passed pawns. Only the frontmost passed
// pawn on each file is considered a true passed pawn.
if (backward)
value -= Backward[opposed][f];
if (backward)
value -= Backward[opposed][f];
- if (connected)
- value += Connected[f][relative_rank(Us, s)];
+ if (connected) {
+ int bonus = Connected[rr];
+ if (ourPawns & adjacent_files_bb(f) & rank_bb(r))
+ bonus += (Connected[rr+1] - Connected[rr]) / 2;
+ value += make_score(bonus / 2, bonus >> opposed);
+ }
- value += Lever[relative_rank(Us, s)];
-
- if (candidate)
- {
- value += CandidatePassed[relative_rank(Us, s)];
-
- if (!doubled)
- e->candidatePawns[Us] |= s;
- }
}
b = e->semiopenFiles[Us] ^ 0xFF;
}
b = e->semiopenFiles[Us] ^ 0xFF;
-/// init() initializes some tables by formula instead of hard-coding their values
-
-void init() {
-
- const int bonusByFile[] = { 1, 3, 3, 4, 4, 3, 3, 1 };
-
- for (Rank r = RANK_1; r < RANK_8; ++r)
- for (File f = FILE_A; f <= FILE_H; ++f)
- {
- int bonus = r * (r - 1) * (r - 2) + bonusByFile[f] * (r / 2 + 1);
- Connected[f][r] = make_score(bonus, bonus);
- }
-}
-
-
/// probe() takes a position as input, computes a Entry object, and returns a
/// pointer to it. The result is also stored in a hash table, so we don't have
/// to recompute everything when the same pawn structure occurs again.
/// probe() takes a position as input, computes a Entry object, and returns a
/// pointer to it. The result is also stored in a hash table, so we don't have
/// to recompute everything when the same pawn structure occurs again.
Score pawns_value() const { return value; }
Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
Score pawns_value() const { return value; }
Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
- Bitboard candidate_pawns(Color c) const { return candidatePawns[c]; }
int semiopen_file(Color c, File f) const {
return semiopenFiles[c] & (1 << f);
int semiopen_file(Color c, File f) const {
return semiopenFiles[c] & (1 << f);
Key key;
Score value;
Bitboard passedPawns[COLOR_NB];
Key key;
Score value;
Bitboard passedPawns[COLOR_NB];
- Bitboard candidatePawns[COLOR_NB];
Bitboard pawnAttacks[COLOR_NB];
Square kingSquares[COLOR_NB];
Score kingSafety[COLOR_NB];
Bitboard pawnAttacks[COLOR_NB];
Square kingSquares[COLOR_NB];
Score kingSafety[COLOR_NB];
typedef HashTable<Entry, 16384> Table;
typedef HashTable<Entry, 16384> Table;
Entry* probe(const Position& pos, Table& entries);
} // namespace Pawns
Entry* probe(const Position& pos, Table& entries);
} // namespace Pawns