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Separate pseudo-royalty from extinction #901

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99ed489
Separate pseudo-royalty from extinction
ianfab Oct 5, 2023
e6a0077
Merge branch 'master' into pseudo_royal_new
ianfab Aug 17, 2025
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6 changes: 3 additions & 3 deletions src/apiutil.h
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Original file line number Diff line number Diff line change
Expand Up @@ -368,14 +368,14 @@ inline bool has_insufficient_material(Color c, const Position& pos) {
// Other win rules
if ( pos.captures_to_hand()
|| pos.count_in_hand(c, ALL_PIECES)
|| (pos.extinction_value() != VALUE_NONE && !pos.extinction_pseudo_royal())
|| (pos.extinction_value() != VALUE_NONE && (pos.extinction_piece_types() & ~pos.pseudo_royal_types()))
|| (pos.flag_region(c) && pos.count(c, pos.flag_piece(c))))
return false;

// Restricted pieces
Bitboard restricted = pos.pieces(~c, KING);
// Atomic kings can not help checkmating
if (pos.extinction_pseudo_royal() && pos.blast_on_capture() && (pos.extinction_piece_types() & COMMONER))
if (pos.pseudo_royal_types() & COMMONER)
restricted |= pos.pieces(c, COMMONER);
for (PieceSet ps = pos.piece_types(); ps;)
{
Expand Down Expand Up @@ -414,7 +414,7 @@ inline bool has_insufficient_material(Color c, const Position& pos) {

inline Bitboard checked(const Position& pos) {
return (pos.checkers() ? square_bb(pos.square<KING>(pos.side_to_move())) : Bitboard(0))
| (pos.extinction_pseudo_royal() ? pos.checked_pseudo_royals(pos.side_to_move()) : Bitboard(0));
| (pos.pseudo_royal_types() ? pos.checked_pseudo_royals(pos.side_to_move()) : Bitboard(0));
}

namespace FEN {
Expand Down
17 changes: 14 additions & 3 deletions src/parser.cpp
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Expand Up @@ -348,6 +348,16 @@ Variant* VariantParser<DoCheck>::parse(Variant* v) {
parse_attribute<false>("whiteDropRegion", v->dropRegion[WHITE]);
parse_attribute<false>("blackDropRegion", v->dropRegion[BLACK]);

bool deprecatedPseudoRoyal = false;
parse_attribute<false>("extinctionPseudoRoyal", deprecatedPseudoRoyal);
if (deprecatedPseudoRoyal)
{
parse_attribute("extinctionPieceTypes", v->pseudoRoyalTypes, v->pieceToChar);
// pseudo royal count is one more than extinction count
if (parse_attribute("extinctionPieceCount", v->pseudoRoyalCount))
v->pseudoRoyalCount++;
}

bool dropOnTop = false;
parse_attribute<false>("dropOnTop", dropOnTop);
if (dropOnTop) v->enclosingDrop=TOP;
Expand Down Expand Up @@ -511,10 +521,11 @@ Variant* VariantParser<DoCheck>::parse(Variant* v) {
parse_attribute("shogiPawnDropMateIllegal", v->shogiPawnDropMateIllegal);
parse_attribute("shatarMateRule", v->shatarMateRule);
parse_attribute("bikjangRule", v->bikjangRule);
parse_attribute("pseudoRoyalTypes", v->pseudoRoyalTypes, v->pieceToChar);
parse_attribute("pseudoRoyalCount", v->pseudoRoyalCount);
parse_attribute("dupleCheck", v->dupleCheck);
parse_attribute("extinctionValue", v->extinctionValue);
parse_attribute("extinctionClaim", v->extinctionClaim);
parse_attribute("extinctionPseudoRoyal", v->extinctionPseudoRoyal);
parse_attribute("dupleCheck", v->dupleCheck);
// extinction piece types
parse_attribute("extinctionPieceTypes", v->extinctionPieceTypes, v->pieceToChar);
parse_attribute("extinctionPieceCount", v->extinctionPieceCount);
Expand Down Expand Up @@ -635,7 +646,7 @@ Variant* VariantParser<DoCheck>::parse(Variant* v) {
// 1. In blast variants, moving a (pseudo-)royal blastImmuneType into another piece is legal.
// 2. In blast variants, capturing a piece next to a (pseudo-)royal blastImmuneType is legal.
// 3. Moving a (pseudo-)royal mutuallyImmuneType into a square threatened by the same type is legal.
if ((v->extinctionPseudoRoyal) || (v->pieceTypes & KING))
if (v->pseudoRoyalTypes || (v->pieceTypes & KING))
{
if (v->blastImmuneTypes)
std::cerr << "Can not use kings or pseudo-royal with blastImmuneTypes." << std::endl;
Expand Down
22 changes: 11 additions & 11 deletions src/position.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -591,17 +591,17 @@ void Position::set_check_info(StateInfo* si) const {
si->bikjang = var->bikjangRule && ksq != SQ_NONE ? bool(attacks_bb(sideToMove, ROOK, ksq, pieces()) & pieces(sideToMove, KING)) : false;
si->chased = var->chasingRule ? chased() : Bitboard(0);
si->legalCapture = NO_VALUE;
if (var->extinctionPseudoRoyal)
if (var->pseudoRoyalTypes)
{
si->pseudoRoyalCandidates = 0;
si->pseudoRoyals = 0;
for (PieceSet ps = extinction_piece_types(); ps;)
for (PieceSet ps = pseudo_royal_types(); ps;)
{
PieceType pt = pop_lsb(ps);
si->pseudoRoyalCandidates |= pieces(pt);
if (count(sideToMove, pt) <= var->extinctionPieceCount + 1)
if (count(sideToMove, pt) <= var->pseudoRoyalCount)
si->pseudoRoyals |= pieces(sideToMove, pt);
if (count(~sideToMove, pt) <= var->extinctionPieceCount + 1)
if (count(~sideToMove, pt) <= var->pseudoRoyalCount)
si->pseudoRoyals |= pieces(~sideToMove, pt);
}
}
Expand Down Expand Up @@ -1005,7 +1005,7 @@ Bitboard Position::attackers_to(Square s, Bitboard occupied) const {
/// Position::checked_pseudo_royals computes a bitboard of
/// all pseudo-royal pieces of a particular color that are in check
Bitboard Position::checked_pseudo_royals(Color c) const {
assert(extinction_pseudo_royal());
assert(pseudo_royal_types());
Bitboard checked = 0;
Bitboard pseudoRoyals = st->pseudoRoyals & pieces(c);
Bitboard pseudoRoyalsTheirs = st->pseudoRoyals & pieces(~c);
Expand Down Expand Up @@ -1113,7 +1113,7 @@ bool Position::legal(Move m) const {
}

// Check for attacks to pseudo-royal pieces
if (var->extinctionPseudoRoyal)
if (var->pseudoRoyalTypes)
{
Square kto = to;
Bitboard occupied = (type_of(m) != DROP ? pieces() ^ from : pieces());
Expand Down Expand Up @@ -1149,9 +1149,9 @@ bool Position::legal(Move m) const {
Bitboard pseudoRoyalsTheirs = st->pseudoRoyals & pieces(~sideToMove);
if (is_ok(from) && (pseudoRoyals & from))
pseudoRoyals ^= square_bb(from) ^ kto;
if (type_of(m) == PROMOTION && (extinction_piece_types() & promotion_type(m)))
if (type_of(m) == PROMOTION && (pseudo_royal_types() & promotion_type(m)))
{
if (count(sideToMove, promotion_type(m)) > extinction_piece_count())
if (count(sideToMove, promotion_type(m)) >= var->pseudoRoyalCount)
// increase in count leads to loss of pseudo-royalty
pseudoRoyals &= ~pieces(sideToMove, promotion_type(m));
else
Expand All @@ -1163,7 +1163,7 @@ bool Position::legal(Move m) const {
return false;
// Petrifiable pseudo-royals can't capture
Bitboard attackerCandidatesTheirs = occupied & ~square_bb(kto);
for (PieceSet ps = var->petrifyOnCaptureTypes & extinction_piece_types(); ps;)
for (PieceSet ps = var->petrifyOnCaptureTypes & pseudo_royal_types(); ps;)
attackerCandidatesTheirs &= ~pieces(~us, pop_lsb(ps));
// Check for legality unless we capture a pseudo-royal piece
if (!(pseudoRoyalsTheirs & ~occupied))
Expand All @@ -1181,7 +1181,7 @@ bool Position::legal(Move m) const {
Bitboard pseudoRoyalCandidates = st->pseudoRoyalCandidates & pieces(sideToMove);
if (is_ok(from) && (pseudoRoyalCandidates & from))
pseudoRoyalCandidates ^= square_bb(from) ^ kto;
if (type_of(m) == PROMOTION && (extinction_piece_types() & promotion_type(m)))
if (type_of(m) == PROMOTION && (pseudo_royal_types() & promotion_type(m)))
pseudoRoyalCandidates |= kto;
bool allCheck = bool(pseudoRoyalCandidates);
while (allCheck && pseudoRoyalCandidates)
Expand Down Expand Up @@ -2724,7 +2724,7 @@ bool Position::is_immediate_game_end(Value& result, int ply) const {

// Extinction
// Extinction does not apply for pseudo-royal pieces, because they can not be captured
if (extinction_value() != VALUE_NONE && (!var->extinctionPseudoRoyal || blast_on_capture()))
if (extinction_value() != VALUE_NONE)
{
for (Color c : { ~sideToMove, sideToMove })
for (PieceSet ps = extinction_piece_types(); ps;)
Expand Down
8 changes: 4 additions & 4 deletions src/position.h
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Original file line number Diff line number Diff line change
Expand Up @@ -208,7 +208,7 @@ class Position {
bool extinction_single_piece() const;
int extinction_piece_count() const;
int extinction_opponent_piece_count() const;
bool extinction_pseudo_royal() const;
PieceSet pseudo_royal_types() const;
PieceType flag_piece(Color c) const;
Bitboard flag_region(Color c) const;
bool flag_move() const;
Expand Down Expand Up @@ -919,7 +919,7 @@ inline Value Position::stalemate_value(int ply) const {
return c == 0 ? VALUE_DRAW : convert_mate_value(c < 0 ? var->stalemateValue : -var->stalemateValue, ply);
}
// Check for checkmate of pseudo-royal pieces
if (var->extinctionPseudoRoyal)
if (var->pseudoRoyalTypes)
{
Bitboard pseudoRoyals = st->pseudoRoyals & pieces(sideToMove);
Bitboard pseudoRoyalsTheirs = st->pseudoRoyals & pieces(~sideToMove);
Expand Down Expand Up @@ -1031,9 +1031,9 @@ inline int Position::extinction_opponent_piece_count() const {
return var->extinctionOpponentPieceCount;
}

inline bool Position::extinction_pseudo_royal() const {
inline PieceSet Position::pseudo_royal_types() const {
assert(var != nullptr);
return var->extinctionPseudoRoyal;
return var->pseudoRoyalTypes;
}

inline PieceType Position::flag_piece(Color c) const {
Expand Down
2 changes: 1 addition & 1 deletion src/psqt.cpp
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Expand Up @@ -323,7 +323,7 @@ void init(const Variant* v) {
: pt == KING ? KingBonus[std::clamp(Rank(r - pawnRank + 1), RANK_1, RANK_8)][std::min(f, FILE_D)] * (1 + v->capturesToHand)
: pt <= QUEEN ? Bonus[pc][std::min(r, RANK_8)][std::min(f, FILE_D)] * (1 + v->blastOnCapture)
: pt == HORSE ? Bonus[KNIGHT][std::min(r, RANK_8)][std::min(f, FILE_D)]
: pt == COMMONER && v->extinctionValue == -VALUE_MATE && (v->extinctionPieceTypes & COMMONER) ? KingBonus[std::clamp(Rank(r - pawnRank + 1), RANK_1, RANK_8)][std::min(f, FILE_D)]
: pt == COMMONER && ((v->pseudoRoyalTypes & COMMONER) || (v->extinctionValue == -VALUE_MATE && (v->extinctionPieceTypes & COMMONER))) ? KingBonus[std::clamp(Rank(r - pawnRank + 1), RANK_1, RANK_8)][std::min(f, FILE_D)]
: isSlider ? make_score(5, 5) * (2 * f + std::max(std::min(r, Rank(v->maxRank - r)), RANK_1) - v->maxFile - 1)
: isPawn ? make_score(5, 5) * (2 * f - v->maxFile)
: make_score(10, 10) * (1 + isSlowLeaper) * (f + std::max(std::min(r, Rank(v->maxRank - r)), RANK_1) - v->maxFile / 2));
Expand Down
30 changes: 16 additions & 14 deletions src/variant.cpp
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Expand Up @@ -485,9 +485,7 @@ namespace {
v->remove_piece(KING);
v->add_piece(COMMONER, 'k');
v->castlingKingPiece[WHITE] = v->castlingKingPiece[BLACK] = COMMONER;
v->extinctionValue = -VALUE_MATE;
v->extinctionPieceTypes = piece_set(COMMONER);
v->extinctionPseudoRoyal = true;
v->pseudoRoyalTypes = piece_set(COMMONER);
v->petrifyOnCaptureTypes = piece_set(COMMONER) | QUEEN | ROOK | BISHOP | KNIGHT;
return v;
}
Expand All @@ -509,7 +507,7 @@ namespace {
// https://en.wikipedia.org/wiki/Atomic_chess
Variant* atomic_variant() {
Variant* v = nocheckatomic_variant()->init();
v->extinctionPseudoRoyal = true;
v->pseudoRoyalTypes = piece_set(COMMONER);
v->endgameEval = EG_EVAL_ATOMIC;
return v;
}
Expand Down Expand Up @@ -1076,8 +1074,9 @@ namespace {
v->promotionLimit[COMMONER] = 2;
v->enPassantRegion[WHITE] = 0;
v->enPassantRegion[BLACK] = 0;
v->extinctionPieceCount = 0;
v->extinctionPseudoRoyal = true;
v->extinctionValue = VALUE_NONE;
v->pseudoRoyalTypes = piece_set(COMMONER);
v->pseudoRoyalCount = 1;
v->dupleCheck = true;
return v;
}
Expand All @@ -1104,10 +1103,8 @@ namespace {
// https://www.chessvariants.com/winning.dir/coregal.html
Variant* coregal_variant() {
Variant* v = chess_variant_base()->init();
v->extinctionValue = -VALUE_MATE;
v->extinctionPieceTypes = piece_set(QUEEN);
v->extinctionPseudoRoyal = true;
v->extinctionPieceCount = 64; // no matter how many queens, all are royal
v->pseudoRoyalTypes = piece_set(QUEEN);
v->pseudoRoyalCount = 64; // no matter how many queens, all are royal
return v;
}
// Clobber
Expand Down Expand Up @@ -1265,10 +1262,8 @@ namespace {
v->pieceDrops = false;
v->promotedPieceType[CUSTOM_PIECE_1] = COMMONER;
v->castlingKingPiece[WHITE] = v->castlingKingPiece[BLACK] = COMMONER;
v->extinctionValue = -VALUE_MATE;
v->extinctionPieceTypes = piece_set(COMMONER);
v->extinctionPseudoRoyal = true;
v->extinctionPieceCount = 0;
v->pseudoRoyalTypes = piece_set(COMMONER);
v->pseudoRoyalCount = 1;
return v;
}
// Yari shogi
Expand Down Expand Up @@ -1963,6 +1958,11 @@ Variant* Variant::conclude() {
doubleStepRegion[WHITE] = doubleStepRegion[BLACK] = 0;
if (!doubleStepRegion[WHITE] && !doubleStepRegion[BLACK])
doubleStep = false;
if (extinctionValue == VALUE_NONE || !(extinctionPieceTypes & pieceTypes))
{
extinctionValue = VALUE_NONE;
extinctionPieceTypes = NO_PIECE_SET;
}

// Determine optimizations
bool restrictedMobility = false;
Expand All @@ -1985,6 +1985,7 @@ Variant* Variant::conclude() {

// Initialize calculated NNUE properties
nnueKing = pieceTypes & KING ? KING
: pseudoRoyalCount == 1 && popcount(pseudoRoyalTypes) == 1 ? lsb(pseudoRoyalTypes)
: extinctionPieceCount == 0 && (extinctionPieceTypes & COMMONER) ? COMMONER
: NO_PIECE_TYPE;
// The nnueKing has to present exactly once and must not change in count
Expand Down Expand Up @@ -2068,6 +2069,7 @@ Variant* Variant::conclude() {
||
( endgameEval == EG_EVAL_CHESS
&& extinctionValue == VALUE_NONE
&& !pseudoRoyalTypes
&& checkmateValue == -VALUE_MATE
&& stalemateValue == VALUE_DRAW
&& !materialCounting
Expand Down
3 changes: 2 additions & 1 deletion src/variant.h
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Expand Up @@ -136,7 +136,8 @@ struct Variant {
bool bikjangRule = false;
Value extinctionValue = VALUE_NONE;
bool extinctionClaim = false;
bool extinctionPseudoRoyal = false;
PieceSet pseudoRoyalTypes = NO_PIECE_SET;
int pseudoRoyalCount = 1;
bool dupleCheck = false;
PieceSet extinctionPieceTypes = NO_PIECE_SET;
int extinctionPieceCount = 0;
Expand Down
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