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7 piece syzygy TB support #557

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7 piece syzygy TB support #557

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62 changes: 44 additions & 18 deletions src/syzygy/tbprobe.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -55,13 +55,13 @@ int Tablebases::MaxCardinality;

namespace {

constexpr int TBPIECES = 6; // Max number of supported pieces
constexpr int TBPIECES = 7; // Max number of supported pieces

enum { BigEndian, LittleEndian };
enum TBType { KEY, WDL, DTZ }; // Used as template parameter

// Each table has a set of flags: all of them refer to DTZ tables, the last one to WDL tables
enum TBFlag { STM = 1, Mapped = 2, WinPlies = 4, LossPlies = 8, SingleValue = 128 };
enum TBFlag { STM = 1, Mapped = 2, WinPlies = 4, LossPlies = 8, LongDTZ = 16, SingleValue = 128 };

inline WDLScore operator-(WDLScore d) { return WDLScore(-int(d)); }
inline Square operator^=(Square& s, int i) { return s = Square(int(s) ^ i); }
Expand All @@ -74,9 +74,9 @@ int MapB1H1H7[SQUARE_NB];
int MapA1D1D4[SQUARE_NB];
int MapKK[10][SQUARE_NB]; // [MapA1D1D4][SQUARE_NB]

int Binomial[6][SQUARE_NB]; // [k][n] k elements from a set of n elements
int LeadPawnIdx[5][SQUARE_NB]; // [leadPawnsCnt][SQUARE_NB]
int LeadPawnsSize[5][4]; // [leadPawnsCnt][FILE_A..FILE_D]
int Binomial[7][SQUARE_NB]; // [k][n] k elements from a set of n elements
int LeadPawnIdx[6][SQUARE_NB]; // [leadPawnsCnt][SQUARE_NB]
int LeadPawnsSize[6][4]; // [leadPawnsCnt][FILE_A..FILE_D]

// Comparison function to sort leading pawns in ascending MapPawns[] order
bool pawns_comp(Square i, Square j) { return MapPawns[i] < MapPawns[j]; }
Expand Down Expand Up @@ -155,7 +155,7 @@ struct LR {
Sym get() {
return S == Left ? ((lr[1] & 0xF) << 8) | lr[0] :
S == Right ? (lr[2] << 4) | (lr[1] >> 4) :
S == Value ? lr[0] : (assert(false), Sym(-1));
S == Value ? ((lr[1] & 0xF) << 8) | lr[0] : (assert(false), Sym(-1));
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Update the comment above to indicate that value can also be 12 bits now?

}
};

Expand Down Expand Up @@ -501,7 +501,7 @@ int decompress_pairs(PairsData* d, uint64_t idx) {
uint32_t k = idx / d->span;

// Then we read the corresponding SparseIndex[] entry
uint32_t block = number<uint32_t, LittleEndian>(&d->sparseIndex[k].block);
size_t block = number<uint32_t, LittleEndian>(&d->sparseIndex[k].block);
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Not sure why this change...

int offset = number<uint16_t, LittleEndian>(&d->sparseIndex[k].offset);

// Now compute the difference idx - I(k). From definition of k we know that
Expand Down Expand Up @@ -612,8 +612,13 @@ int map_score(TBTable<DTZ>* entry, File f, int value, WDLScore wdl) {

uint8_t* map = entry->map;
uint16_t* idx = entry->get(0, f)->map_idx;
if (flags & TBFlag::Mapped)
value = map[idx[WDLMap[wdl + 2]] + value];
if (flags & TBFlag::Mapped) {
if (flags & TBFlag::LongDTZ) {
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Indentation is a bit messed up here and the following few lines.

value = ((uint16_t *)map)[idx[WDLMap[wdl + 2]] + value];
} else {
value = map[idx[WDLMap[wdl + 2]] + value];
}
}

// DTZ tables store distance to zero in number of moves or plies. We
// want to return plies, so we have convert to plies when needed.
Expand Down Expand Up @@ -1005,11 +1010,21 @@ uint8_t* set_dtz_map(TBTable<DTZ>& e, uint8_t* data, File maxFile) {
e.map = data;

for (File f = FILE_A; f <= maxFile; ++f) {
if (e.get(0, f)->flags & TBFlag::Mapped)
for (int i = 0; i < 4; ++i) { // Sequence like 3,x,x,x,1,x,0,2,x,x
e.get(0, f)->map_idx[i] = (uint16_t)(data - e.map + 1);
data += *data + 1;
int flags = e.get(0, f)->flags;
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indentation wrong on this line.

if (flags & TBFlag::Mapped) {
if (flags & TBFlag::LongDTZ) {
data += (uintptr_t)data & 1; // Word alignment
for (int i = 0; i < 4; i++) {
e.get(0, f)->map_idx[i] = (uint16_t)((uint16_t *)data - (uint16_t *)e.map + 1);
data += 2 + 2 * number<uint16_t, LittleEndian>(data);
}
} else {
for (int i = 0; i < 4; ++i) { // Sequence like 3,x,x,x,1,x,0,2,x,x
e.get(0, f)->map_idx[i] = (uint16_t)(data - e.map + 1);
data += *data + 1;
}
}
}
}

return data += (uintptr_t)data & 1; // Word alignment
Expand Down Expand Up @@ -1275,7 +1290,7 @@ void Tablebases::init(const std::string& paths) {
Binomial[0][0] = 1;

for (int n = 1; n < 64; n++) // Squares
for (int k = 0; k < 6 && k <= n; ++k) // Pieces
for (int k = 0; k < 7 && k <= n; ++k) // Pieces
Binomial[k][n] = (k > 0 ? Binomial[k - 1][n - 1] : 0)
+ (k < n ? Binomial[k ][n - 1] : 0);

Expand All @@ -1285,9 +1300,9 @@ void Tablebases::init(const std::string& paths) {
// among pawns with same file, the one with lowest rank.
int availableSquares = 47; // Available squares when lead pawn is in a2

// Init the tables for the encoding of leading pawns group: with 6-men TB we
// Init the tables for the encoding of leading pawns group: with 7-men TB we
// can have up to 4 leading pawns (KPPPPK).
for (int leadPawnsCnt = 1; leadPawnsCnt <= 4; ++leadPawnsCnt)
for (int leadPawnsCnt = 1; leadPawnsCnt <= 5; ++leadPawnsCnt)
for (File f = FILE_A; f <= FILE_D; ++f)
{
// Restart the index at every file because TB table is splitted
Expand Down Expand Up @@ -1331,11 +1346,22 @@ void Tablebases::init(const std::string& paths) {
for (PieceType p3 = PAWN; p3 <= p2; ++p3) {
TBTables.add({KING, p1, p2, p3, KING});

for (PieceType p4 = PAWN; p4 <= p3; ++p4)
for (PieceType p4 = PAWN; p4 <= p3; ++p4) {
TBTables.add({KING, p1, p2, p3, p4, KING});

for (PieceType p4 = PAWN; p4 < KING; ++p4)
for (PieceType p5 = PAWN; p5 <= p4; ++p5)
TBTables.add({KING, p1, p2, p3, p4, p5, KING});

for (PieceType p5 = PAWN; p5 < KING; ++p5)
TBTables.add({KING, p1, p2, p3, p4, KING, p5});
}

for (PieceType p4 = PAWN; p4 < KING; ++p4) {
TBTables.add({KING, p1, p2, p3, KING, p4});

for (PieceType p5 = PAWN; p5 <= p4; ++p5)
TBTables.add({KING, p1, p2, p3, KING, p4, p5});
}
}

for (PieceType p3 = PAWN; p3 <= p1; ++p3)
Expand Down