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BadFish/src/syzygy/tbprobe.cpp
Marco Costalba 48ef73fc6c Further cleanup init() functions
2016-04-27 14:33:03 +02:00

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/*
Copyright (c) 2013 Ronald de Man
This file may be redistributed and/or modified without restrictions.
tbprobe.cpp contains the Stockfish-specific routines of the
tablebase probing code. It should be relatively easy to adapt
this code to other chess engines.
*/
#include <algorithm>
#include <cstdint>
#include <cstring> // For std::memset
#include <deque>
#include <list>
#include <fstream>
#include <iostream>
#include <sstream>
#include "../bitboard.h"
#include "../movegen.h"
#include "../position.h"
#include "../search.h"
#include "../thread_win32.h"
#include "../types.h"
#include "tbprobe.h"
#ifndef _WIN32
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#else
#define WIN32_LEAN_AND_MEAN
#define NOMINMAX
#include <windows.h>
#endif
#define TBPIECES 6
using namespace Tablebases;
int Tablebases::MaxCardinality = 0;
namespace {
typedef uint64_t base_t;
inline WDLScore operator-(WDLScore d) { return WDLScore(-int(d)); }
inline WDLScore operator+(WDLScore d1, WDLScore d2) { return WDLScore(int(d1) + int(d2)); }
inline Square operator^=(Square& s, int i) { return s = Square(int(s) ^ i); }
inline Square operator^(Square s, int i) { return Square(int(s) ^ i); }
struct PairsData {
char *indextable;
uint16_t *sizetable;
uint8_t *data;
uint16_t *offset;
uint8_t *symlen;
uint8_t *sympat;
int blocksize;
int idxbits;
int min_len;
base_t base[1]; // C++ complains about base[]...
};
class WDLEntry {
static constexpr uint8_t TB_MAGIC[] = { 0x71, 0xE8, 0x23, 0x5D };
public:
WDLEntry(const Position& pos, Key keys[]);
~WDLEntry();
bool init(const std::string& fname);
char* baseAddress;
uint64_t key;
uint64_t mapping;
uint8_t ready;
uint8_t num;
uint8_t symmetric;
uint8_t has_pawns;
union {
struct {
uint8_t hasUniquePieces;
PairsData* precomp;
int factor[TBPIECES];
uint8_t pieces[TBPIECES];
uint8_t norm[TBPIECES];
} piece[2];
struct {
uint8_t pawns[2];
struct {
PairsData* precomp[2];
int factor[2][TBPIECES];
uint8_t pieces[2][TBPIECES];
uint8_t norm[2][TBPIECES];
} file[4];
} pawn;
};
};
class DTZEntry {
static constexpr uint8_t TB_MAGIC[] = { 0xD7, 0x66, 0x0C, 0xA5 };
public:
DTZEntry(const WDLEntry& wdl, Key keys[]);
~DTZEntry();
bool init(const std::string& fname);
uint64_t keys[2];
char* baseAddress;
uint64_t key;
uint64_t mapping;
uint8_t ready;
uint8_t num;
uint8_t symmetric;
uint8_t has_pawns;
union {
struct {
uint8_t hasUniquePieces;
PairsData* precomp;
int factor[TBPIECES];
uint8_t pieces[TBPIECES];
uint8_t norm[TBPIECES];
uint8_t flags; // accurate, mapped, side
uint16_t map_idx[4];
uint8_t* map;
} piece;
struct {
uint8_t pawns[2];
struct {
PairsData* precomp;
int factor[TBPIECES];
uint8_t pieces[TBPIECES];
uint8_t norm[TBPIECES];
uint8_t flags;
uint16_t map_idx[4];
} file[4];
uint8_t* map;
} pawn;
};
};
const signed char OffdiagA1H8[] = {
0,-1,-1,-1,-1,-1,-1,-1,
1, 0,-1,-1,-1,-1,-1,-1,
1, 1, 0,-1,-1,-1,-1,-1,
1, 1, 1, 0,-1,-1,-1,-1,
1, 1, 1, 1, 0,-1,-1,-1,
1, 1, 1, 1, 1, 0,-1,-1,
1, 1, 1, 1, 1, 1, 0,-1,
1, 1, 1, 1, 1, 1, 1, 0
};
const uint8_t Triangle[] = {
6, 0, 1, 2, 2, 1, 0, 6,
0, 7, 3, 4, 4, 3, 7, 0,
1, 3, 8, 5, 5, 8, 3, 1,
2, 4, 5, 9, 9, 5, 4, 2,
2, 4, 5, 9, 9, 5, 4, 2,
1, 3, 8, 5, 5, 8, 3, 1,
0, 7, 3, 4, 4, 3, 7, 0,
6, 0, 1, 2, 2, 1, 0, 6
};
const uint8_t Lower[] = {
28, 0, 1, 2, 3, 4, 5, 6,
0, 29, 7, 8, 9, 10, 11, 12,
1, 7, 30, 13, 14, 15, 16, 17,
2, 8, 13, 31, 18, 19, 20, 21,
3, 9, 14, 18, 32, 22, 23, 24,
4, 10, 15, 19, 22, 33, 25, 26,
5, 11, 16, 20, 23, 25, 34, 27,
6, 12, 17, 21, 24, 26, 27, 35
};
const uint8_t Diag[] = {
0, 0, 0, 0, 0, 0, 0, 8,
0, 1, 0, 0, 0, 0, 9, 0,
0, 0, 2, 0, 0, 10, 0, 0,
0, 0, 0, 3, 11, 0, 0, 0,
0, 0, 0, 12, 4, 0, 0, 0,
0, 0, 13, 0, 0, 5, 0, 0,
0, 14, 0, 0, 0, 0, 6, 0,
15, 0, 0, 0, 0, 0, 0, 7
};
const uint8_t Flap[] = {
0, 0, 0, 0, 0, 0, 0, 0,
0, 6, 12, 18, 18, 12, 6, 0,
1, 7, 13, 19, 19, 13, 7, 1,
2, 8, 14, 20, 20, 14, 8, 2,
3, 9, 15, 21, 21, 15, 9, 3,
4, 10, 16, 22, 22, 16, 10, 4,
5, 11, 17, 23, 23, 17, 11, 5,
0, 0, 0, 0, 0, 0, 0, 0
};
const uint8_t Ptwist[] = {
0, 0, 0, 0, 0, 0, 0, 0,
47, 35, 23, 11, 10, 22, 34, 46,
45, 33, 21, 9, 8, 20, 32, 44,
43, 31, 19, 7, 6, 18, 30, 42,
41, 29, 17, 5, 4, 16, 28, 40,
39, 27, 15, 3, 2, 14, 26, 38,
37, 25, 13, 1, 0, 12, 24, 36,
0, 0, 0, 0, 0, 0, 0, 0
};
const uint8_t Invflap[] = {
8, 16, 24, 32, 40, 48,
9, 17, 25, 33, 41, 49,
10, 18, 26, 34, 42, 50,
11, 19, 27, 35, 43, 51
};
const short KK_idx[10][64] = {
{
-1, -1, -1, 0, 1, 2, 3, 4,
-1, -1, -1, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25,
26, 27, 28, 29, 30, 31, 32, 33,
34, 35, 36, 37, 38, 39, 40, 41,
42, 43, 44, 45, 46, 47, 48, 49,
50, 51, 52, 53, 54, 55, 56, 57
},
{
58, -1, -1, -1, 59, 60, 61, 62,
63, -1, -1, -1, 64, 65, 66, 67,
68, 69, 70, 71, 72, 73, 74, 75,
76, 77, 78, 79, 80, 81, 82, 83,
84, 85, 86, 87, 88, 89, 90, 91,
92, 93, 94, 95, 96, 97, 98, 99,
100,101,102,103,104,105,106,107,
108,109,110,111,112,113,114,115
},
{
116,117, -1, -1, -1,118,119,120,
121,122, -1, -1, -1,123,124,125,
126,127,128,129,130,131,132,133,
134,135,136,137,138,139,140,141,
142,143,144,145,146,147,148,149,
150,151,152,153,154,155,156,157,
158,159,160,161,162,163,164,165,
166,167,168,169,170,171,172,173
},
{
174, -1, -1, -1,175,176,177,178,
179, -1, -1, -1,180,181,182,183,
184, -1, -1, -1,185,186,187,188,
189,190,191,192,193,194,195,196,
197,198,199,200,201,202,203,204,
205,206,207,208,209,210,211,212,
213,214,215,216,217,218,219,220,
221,222,223,224,225,226,227,228
},
{
229,230, -1, -1, -1,231,232,233,
234,235, -1, -1, -1,236,237,238,
239,240, -1, -1, -1,241,242,243,
244,245,246,247,248,249,250,251,
252,253,254,255,256,257,258,259,
260,261,262,263,264,265,266,267,
268,269,270,271,272,273,274,275,
276,277,278,279,280,281,282,283
},
{
284,285,286,287,288,289,290,291,
292,293, -1, -1, -1,294,295,296,
297,298, -1, -1, -1,299,300,301,
302,303, -1, -1, -1,304,305,306,
307,308,309,310,311,312,313,314,
315,316,317,318,319,320,321,322,
323,324,325,326,327,328,329,330,
331,332,333,334,335,336,337,338
},
{
-1, -1,339,340,341,342,343,344,
-1, -1,345,346,347,348,349,350,
-1, -1,441,351,352,353,354,355,
-1, -1, -1,442,356,357,358,359,
-1, -1, -1, -1,443,360,361,362,
-1, -1, -1, -1, -1,444,363,364,
-1, -1, -1, -1, -1, -1,445,365,
-1, -1, -1, -1, -1, -1, -1,446
},
{
-1, -1, -1,366,367,368,369,370,
-1, -1, -1,371,372,373,374,375,
-1, -1, -1,376,377,378,379,380,
-1, -1, -1,447,381,382,383,384,
-1, -1, -1, -1,448,385,386,387,
-1, -1, -1, -1, -1,449,388,389,
-1, -1, -1, -1, -1, -1,450,390,
-1, -1, -1, -1, -1, -1, -1,451
},
{
452,391,392,393,394,395,396,397,
-1, -1, -1, -1,398,399,400,401,
-1, -1, -1, -1,402,403,404,405,
-1, -1, -1, -1,406,407,408,409,
-1, -1, -1, -1,453,410,411,412,
-1, -1, -1, -1, -1,454,413,414,
-1, -1, -1, -1, -1, -1,455,415,
-1, -1, -1, -1, -1, -1, -1,456
},
{
457,416,417,418,419,420,421,422,
-1,458,423,424,425,426,427,428,
-1, -1, -1, -1, -1,429,430,431,
-1, -1, -1, -1, -1,432,433,434,
-1, -1, -1, -1, -1,435,436,437,
-1, -1, -1, -1, -1,459,438,439,
-1, -1, -1, -1, -1, -1,460,440,
-1, -1, -1, -1, -1, -1, -1,461
}
};
const int wdl_to_dtz[] = { -1, -101, 0, 101, 1 };
const int wdl_to_map[] = { 1, 3, 0, 2, 0 };
const uint8_t pa_flags[] = { 8, 0, 0, 0, 4 };
const Value WDL_to_value[] = {
-VALUE_MATE + MAX_PLY + 1,
VALUE_DRAW - 2,
VALUE_DRAW,
VALUE_DRAW + 2,
VALUE_MATE - MAX_PLY - 1
};
const std::string PieceToChar = " PNBRQK";
Mutex TB_mutex;
std::string TBPaths;
std::deque<WDLEntry> WDLTable;
std::list<DTZEntry> DTZTable;
int Binomial[6][64];
int Pawnidx[5][24];
int Pfactor[5][4];
class HashTable {
struct Entry {
Key key;
WDLEntry* ptr;
};
static const int TBHASHBITS = 10;
static const int HSHMAX = 5;
Entry table[1 << TBHASHBITS][HSHMAX];
void insert(Key key, WDLEntry* ptr) {
Entry* entry = table[key >> (64 - TBHASHBITS)];
for (int i = 0; i < HSHMAX; ++i, ++entry)
if (!entry->ptr || entry->key == key) {
entry->key = key;
entry->ptr = ptr;
return;
}
std::cerr << "HSHMAX too low!" << std::endl;
exit(1);
}
public:
WDLEntry* operator[](Key key) {
Entry* entry = table[key >> (64 - TBHASHBITS)];
for (int i = 0; i < HSHMAX; ++i, ++entry)
if (entry->key == key)
return entry->ptr;
return nullptr;
}
void clear() { std::memset(table, 0, sizeof(table)); }
void insert(const std::vector<PieceType>& pieces);
};
HashTable WDLHash;
class TBFile : public std::ifstream {
std::string fname;
public:
// Open the file with the given name found among the TBPaths. TBPaths stores
// the paths to directories where the .rtbw and .rtbz files can be found.
// Multiple directories are separated by ";" on Windows and by ":" on
// Unix-based operating systems.
//
// Example:
// C:\tb\wdl345;C:\tb\wdl6;D:\tb\dtz345;D:\tb\dtz6
TBFile(const std::string& f) {
#ifndef _WIN32
const char SepChar = ':';
#else
const char SepChar = ';';
#endif
std::stringstream ss(TBPaths);
std::string path;
while (std::getline(ss, path, SepChar)) {
fname = path + "/" + f;
std::ifstream::open(fname);
if (is_open())
return;
}
}
// Memory map the file and check it. File should be already open and
// will be closed after mapping.
uint8_t* map(char** baseAddress, uint64_t* mapping, const uint8_t TB_MAGIC[]) {
if (!is_open()) {
std::cerr << "Could not find " << fname << std::endl;
*baseAddress = nullptr;
return nullptr;
}
close();
#ifndef _WIN32
struct stat statbuf;
int fd = ::open(fname.c_str(), O_RDONLY);
fstat(fd, &statbuf);
*mapping = statbuf.st_size;
*baseAddress = (char*)mmap(nullptr, statbuf.st_size, PROT_READ, MAP_SHARED, fd, 0);
::close(fd);
if (*baseAddress == (char*)(-1)) {
std::cerr << "Could not mmap() " << fname << std::endl;
exit(1);
}
#else
HANDLE fd = CreateFile(fname.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
DWORD size_high;
DWORD size_low = GetFileSize(fd, &size_high);
HANDLE mmap = CreateFileMapping(fd, nullptr, PAGE_READONLY, size_high, size_low, nullptr);
CloseHandle(fd);
if (!mmap) {
std::cerr << "CreateFileMapping() failed" << std::endl;
exit(1);
}
*mapping = (uint64_t)mmap;
*baseAddress = (char*)MapViewOfFile(mmap, FILE_MAP_READ, 0, 0, 0);
if (!*baseAddress) {
std::cerr << "MapViewOfFile() failed, name = " << fname
<< ", error = " << GetLastError() << std::endl;
exit(1);
}
#endif
uint8_t* data = (uint8_t*)*baseAddress;
if ( *data++ != TB_MAGIC[0]
|| *data++ != TB_MAGIC[1]
|| *data++ != TB_MAGIC[2]
|| *data++ != TB_MAGIC[3]) {
std::cerr << "Corrupted table in file " << fname << std::endl;
unmap(*baseAddress, *mapping);
*baseAddress = nullptr;
return nullptr;
}
return data;
}
static void unmap(char* baseAddress, uint64_t mapping) {
#ifndef _WIN32
munmap(baseAddress, mapping);
#else
UnmapViewOfFile(baseAddress);
CloseHandle((HANDLE)mapping);
#endif
}
};
WDLEntry::WDLEntry(const Position& pos, Key keys[])
{
memset(this, 0, sizeof(WDLEntry));
key = keys[WHITE];
num = pos.count<ALL_PIECES>(WHITE) + pos.count<ALL_PIECES>(BLACK);
symmetric = (keys[WHITE] == keys[BLACK]);
has_pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
if (has_pawns) {
// FIXME: What it means this one?
bool c = ( !pos.count<PAWN>(BLACK)
|| ( pos.count<PAWN>(WHITE)
&& pos.count<PAWN>(BLACK) >= pos.count<PAWN>(WHITE)));
pawn.pawns[0] = pos.count<PAWN>(c ? WHITE : BLACK);
pawn.pawns[1] = pos.count<PAWN>(c ? BLACK : WHITE);
} else
for (Color c = WHITE; c <= BLACK; ++c)
for (PieceType pt = PAWN; pt < KING; ++pt)
if (popcount(pos.pieces(c, pt)) == 1)
piece[0].hasUniquePieces = piece[1].hasUniquePieces = true;
}
WDLEntry::~WDLEntry()
{
if (baseAddress)
TBFile::unmap(baseAddress, mapping);
if (has_pawns)
for (File f = FILE_A; f <= FILE_D; ++f) {
free(pawn.file[f].precomp[0]);
free(pawn.file[f].precomp[1]);
}
else {
free(piece[0].precomp);
free(piece[1].precomp);
}
}
DTZEntry::DTZEntry(const WDLEntry& wdl, Key k[])
{
memset(this, 0, sizeof(DTZEntry));
keys[0] = k[0];
keys[1] = k[1];
key = wdl.key;
num = wdl.num;
symmetric = wdl.symmetric;
has_pawns = wdl.has_pawns;
if (has_pawns) {
pawn.pawns[0] = wdl.pawn.pawns[0];
pawn.pawns[1] = wdl.pawn.pawns[1];
} else
piece.hasUniquePieces = wdl.piece[0].hasUniquePieces;
}
DTZEntry::~DTZEntry()
{
if (baseAddress)
TBFile::unmap(baseAddress, mapping);
if (has_pawns)
for (File f = FILE_A; f <= FILE_D; ++f)
free(pawn.file[f].precomp);
else
free(piece.precomp);
}
// Given a position with 6 or fewer pieces, produce a text string
// of the form KQPvKRP, where "KQP" represents the white pieces if
// mirror == false and the black pieces if mirror == true.
std::string file_name(const Position& pos, bool mirror)
{
std::string w, b;
for (PieceType pt = KING; pt >= PAWN; --pt) {
w += std::string(popcount(pos.pieces(WHITE, pt)), PieceToChar[pt]);
b += std::string(popcount(pos.pieces(BLACK, pt)), PieceToChar[pt]);
}
return mirror ? b + 'v' + w : w + 'v' + b;
}
void HashTable::insert(const std::vector<PieceType>& pieces)
{
StateInfo st;
Position pos;
std::string code;
for (PieceType pt : pieces)
code += PieceToChar[pt];
int bk = code.find('K', 1); // Black king
TBFile f(code.substr(0, bk) + 'v' + code.substr(bk) + ".rtbw");
if (!f.is_open())
return;
f.close();
if (int(pieces.size()) > Tablebases::MaxCardinality)
Tablebases::MaxCardinality = pieces.size();
Key keys[] = { pos.set(code, WHITE, &st).material_key(),
pos.set(code, BLACK, &st).material_key() };
WDLTable.push_back(WDLEntry(pos.set(code, WHITE, &st), keys));
insert(keys[WHITE], &WDLTable.back());
insert(keys[BLACK], &WDLTable.back());
}
uint64_t encode_piece(uint8_t hasUniquePieces, uint8_t* norm, Square* pos, int* factor, int n)
{
uint64_t idx;
int i;
if (file_of(pos[0]) > FILE_D)
for (i = 0; i < n; ++i)
pos[i] ^= 7; // Mirror SQ_H1 -> SQ_A1
if (rank_of(pos[0]) > RANK_4)
for (i = 0; i < n; ++i)
pos[i] ^= 070; // Vertical flip SQ_A8 -> SQ_A1
for (i = 0; i < n; ++i)
if (OffdiagA1H8[pos[i]])
break; // First piece not on A1-H8 diagonal
if (i < (hasUniquePieces ? 3 : 2) && OffdiagA1H8[pos[i]] > 0)
for (i = 0; i < n; ++i)
pos[i] = Square(((pos[i] >> 3) | (pos[i] << 3)) & 63); // Flip about the A1-H8 diagonal
if (hasUniquePieces) {
// There are unique pieces other than W_KING and B_KING
i = pos[1] > pos[0];
int j = (pos[2] > pos[0]) + (pos[2] > pos[1]);
if (OffdiagA1H8[pos[0]])
idx = Triangle[pos[0]] * 63*62 + (pos[1] - i) * 62 + (pos[2] - j);
else if (OffdiagA1H8[pos[1]])
idx = 6*63*62 + Diag[pos[0]] * 28*62 + Lower[pos[1]] * 62 + pos[2] - j;
else if (OffdiagA1H8[pos[2]])
idx = 6*63*62 + 4*28*62 + (Diag[pos[0]]) * 7*28 + (Diag[pos[1]] - i) * 28 + Lower[pos[2]];
else
idx = 6*63*62 + 4*28*62 + 4*7*28 + (Diag[pos[0]] * 7*6) + (Diag[pos[1]] - i) * 6 + (Diag[pos[2]] - j);
i = 3;
} else {
idx = KK_idx[Triangle[pos[0]]][pos[1]];
i = 2;
}
idx *= factor[0];
while (i < n) {
int t = norm[i];
std::sort(&pos[i], &pos[i + t]);
uint64_t s = 0;
for (int l = i; l < i + t; ++l) {
int j = 0;
for (int k = 0; k < i; ++k)
j += pos[l] > pos[k];
s += Binomial[l - i + 1][pos[l] - j];
}
idx += s * factor[i];
i += t;
}
return idx;
}
// determine file of leftmost pawn and sort pawns
File pawn_file(uint8_t pawns[], Square *pos)
{
static const File file_to_file[] = {
FILE_A, FILE_B, FILE_C, FILE_D, FILE_D, FILE_C, FILE_B, FILE_A
};
for (int i = 1; i < pawns[0]; ++i)
if (Flap[pos[0]] > Flap[pos[i]])
std::swap(pos[0], pos[i]);
return file_to_file[pos[0] & 7];
}
uint64_t encode_pawn(uint8_t pawns[], uint8_t *norm, Square *pos, int *factor, int n)
{
int i;
if (pos[0] & 4)
for (i = 0; i < n; ++i)
pos[i] ^= 7;
for (i = 1; i < pawns[0]; ++i)
for (int j = i + 1; j < pawns[0]; ++j)
if (Ptwist[pos[i]] < Ptwist[pos[j]])
std::swap(pos[i], pos[j]);
int t = pawns[0] - 1;
uint64_t idx = Pawnidx[t][Flap[pos[0]]];
for (i = t; i > 0; --i)
idx += Binomial[t - i + 1][Ptwist[pos[i]]];
idx *= factor[0];
// remaining pawns
i = pawns[0];
t = i + pawns[1];
if (t > i) {
std::sort(&pos[i], &pos[t]);
uint64_t s = 0;
for (int m = i; m < t; ++m) {
int j = 0;
for (int k = 0; k < i; ++k)
j += pos[m] > pos[k];
s += Binomial[m - i + 1][pos[m] - j - 8];
}
idx += s * factor[i];
i = t;
}
while (i < n) {
t = norm[i];
std::sort(&pos[i], &pos[i + t]);
uint64_t s = 0;
for (int l = i; l < i + t; ++l) {
int j = 0;
for (int k = 0; k < i; ++k)
j += pos[l] > pos[k];
s += Binomial[l - i + 1][pos[l] - j];
}
idx += s * factor[i];
i += t;
}
return idx;
}
template<typename T>
uint64_t set_factors(T& p, int num, int order)
{
int n = 64 - p.norm[0];
uint64_t result = 1;
for (int i = p.norm[0], k = 0; i < num || k == order; ++k) {
if (k == order) {
p.factor[0] = (int)result;
result *= p.hasUniquePieces ? 31332 : 462;
} else {
p.factor[i] = (int)result;
result *= Binomial[p.norm[i]][n];
n -= p.norm[i];
i += p.norm[i];
}
}
return result;
}
uint64_t calc_factors_pawn(int *factor, int num, int order, int order2, uint8_t *norm, File f)
{
assert(FILE_A <= f && f <= FILE_D);
int i = norm[0];
if (order2 < 0x0f)
i += norm[i];
int n = 64 - i;
uint64_t result = 1;
for (int k = 0; i < num || k == order || k == order2; ++k) {
if (k == order) {
factor[0] = (int)result;
result *= Pfactor[norm[0] - 1][f];
} else if (k == order2) {
factor[norm[0]] = (int)result;
result *= Binomial[norm[norm[0]]][48 - norm[0]];
} else {
factor[i] = (int)result;
result *= Binomial[norm[i]][n];
n -= norm[i];
i += norm[i];
}
}
return result;
}
template<typename T>
void set_norms(T& p, int num)
{
for (int i = 0; i < num; ++i)
p.norm[i] = 0;
p.norm[0] = p.hasUniquePieces ? 3 : 2;
for (int i = p.norm[0]; i < num; i += p.norm[i])
for (int j = i; j < num && p.pieces[j] == p.pieces[i]; ++j)
++p.norm[i];
}
void set_norm_pawn(uint8_t pawns[], uint8_t *norm, uint8_t *pieces, int num)
{
int i, j;
for (i = 0; i < num; ++i)
norm[i] = 0;
norm[0] = pawns[0];
if (pawns[1]) norm[pawns[0]] = pawns[1];
for (i = pawns[0] + pawns[1]; i < num; i += norm[i])
for (j = i; j < num && pieces[j] == pieces[i]; ++j)
++norm[i];
}
void calc_symlen(PairsData *d, int s, char *tmp)
{
int s1, s2;
uint8_t* w = d->sympat + 3 * s;
s2 = (w[2] << 4) | (w[1] >> 4);
if (s2 == 0x0fff)
d->symlen[s] = 0;
else {
s1 = ((w[1] & 0xf) << 8) | w[0];
if (!tmp[s1])
calc_symlen(d, s1, tmp);
if (!tmp[s2])
calc_symlen(d, s2, tmp);
d->symlen[s] = uint8_t(d->symlen[s1] + d->symlen[s2] + 1);
}
tmp[s] = 1;
}
uint16_t ReadUshort(uint8_t* d)
{
return uint16_t(d[0] | (d[1] << 8));
}
uint32_t ReadUint32(uint8_t* d)
{
return d[0] | (d[1] << 8) | (d[2] << 16) | (d[3] << 24);
}
PairsData *setup_pairs(uint8_t *data, uint64_t tb_size, uint64_t *size, unsigned char **next, uint8_t *flags, int wdl)
{
PairsData *d;
int i;
*flags = data[0];
if (data[0] & 0x80) {
d = (PairsData *)malloc(sizeof(PairsData));
d->idxbits = 0;
if (wdl)
d->min_len = data[1];
else
d->min_len = 0;
*next = data + 2;
size[0] = size[1] = size[2] = 0;
return d;
}
int blocksize = data[1];
int idxbits = data[2];
int real_num_blocks = ReadUint32(&data[4]);
int num_blocks = real_num_blocks + *(uint8_t *)(&data[3]);
int max_len = data[8];
int min_len = data[9];
int h = max_len - min_len + 1;
int num_syms = ReadUshort(&data[10 + 2 * h]);
d = (PairsData *)malloc(sizeof(PairsData) + (h - 1) * sizeof(base_t) + num_syms);
d->blocksize = blocksize;
d->idxbits = idxbits;
d->offset = (uint16_t*)(&data[10]);
d->symlen = ((uint8_t *)d) + sizeof(PairsData) + (h - 1) * sizeof(base_t);
d->sympat = &data[12 + 2 * h];
d->min_len = min_len;
*next = &data[12 + 2 * h + 3 * num_syms + (num_syms & 1)];
uint64_t num_indices = (tb_size + (1ULL << idxbits) - 1) >> idxbits;
size[0] = 6ULL * num_indices;
size[1] = 2ULL * num_blocks;
size[2] = (1ULL << blocksize) * real_num_blocks;
// char tmp[num_syms];
char tmp[4096];
for (i = 0; i < num_syms; ++i)
tmp[i] = 0;
for (i = 0; i < num_syms; ++i)
if (!tmp[i])
calc_symlen(d, i, tmp);
d->base[h - 1] = 0;
for (i = h - 2; i >= 0; --i)
d->base[i] = (d->base[i + 1] + ReadUshort((uint8_t*)(d->offset + i)) - ReadUshort((uint8_t*)(d->offset + i + 1))) / 2;
for (i = 0; i < h; ++i)
d->base[i] <<= 64 - (min_len + i);
d->offset -= d->min_len;
return d;
}
bool WDLEntry::init(const std::string& fname)
{
uint8_t* next;
uint64_t tb_size[8];
uint64_t size[8 * 3];
uint8_t flags;
uint8_t* data = TBFile(fname).map(&baseAddress, &mapping, TB_MAGIC);
if (!data)
return false;
int split = *data & 1;
File maxFile = *data & 2 ? FILE_D : FILE_A;
data++;
if (!has_pawns) {
int order[] = { *data & 0xF, *data >> 4 };
data++;
for (int i = 0; i < num; ++i, ++data) {
piece[0].pieces[i] = *data & 0xF;
piece[1].pieces[i] = *data >> 4;
}
for (int i = 0; i < 2; ++i) {
set_norms(piece[i], num);
tb_size[i] = set_factors(piece[i], num, order[i]);
}
data += (uintptr_t)data & 1;
piece[0].precomp = setup_pairs(data, tb_size[0], &size[0], &next, &flags, 1);
data = next;
if (split) {
piece[1].precomp = setup_pairs(data, tb_size[1], &size[3], &next, &flags, 1);
data = next;
} else
piece[1].precomp = nullptr;
piece[0].precomp->indextable = (char*)data;
data += size[0];
if (split) {
piece[1].precomp->indextable = (char*)data;
data += size[3];
}
piece[0].precomp->sizetable = (uint16_t*)data;
data += size[1];
if (split) {
piece[1].precomp->sizetable = (uint16_t*)data;
data += size[4];
}
data = (uint8_t*)(((uintptr_t)data + 0x3f) & ~0x3F);
piece[0].precomp->data = data;
data += size[2];
if (split) {
data = (uint8_t*)(((uintptr_t)data + 0x3F) & ~0x3F);
piece[1].precomp->data = data;
}
} else {
bool p = (pawn.pawns[1] > 0);
for (File f = FILE_A; f <= FILE_D; ++f) {
int order1[] = { *data & 0x0F, *data >> 4 };
data++;
int order2[] = { p ? *data & 0xF : 0xF,
p ? *data >> 4 : 0xF };
data += p;
for (int i = 0; i < num; ++i, ++data) {
pawn.file[f].pieces[0][i] = *data & 0xF;
pawn.file[f].pieces[1][i] = *data >> 4;
}
for (int i = 0; i < 2; ++i) {
set_norm_pawn(pawn.pawns, pawn.file[f].norm[i], pawn.file[f].pieces[i], num);
tb_size[2 * f + i] = calc_factors_pawn(pawn.file[f].factor[i], num, order1[i], order2[i], pawn.file[f].norm[i], f);
}
}
data += (uintptr_t)data & 1;
for (File f = FILE_A; f <= maxFile; ++f) {
pawn.file[f].precomp[0] = setup_pairs(data, tb_size[2 * f], &size[6 * f], &next, &flags, 1);
data = next;
if (split) {
pawn.file[f].precomp[1] = setup_pairs(data, tb_size[2 * f + 1], &size[6 * f + 3], &next, &flags, 1);
data = next;
} else
pawn.file[f].precomp[1] = nullptr;
}
for (File f = FILE_A; f <= maxFile; ++f) {
pawn.file[f].precomp[0]->indextable = (char *)data;
data += size[6 * f];
if (split) {
pawn.file[f].precomp[1]->indextable = (char *)data;
data += size[6 * f + 3];
}
}
for (File f = FILE_A; f <= maxFile; ++f) {
pawn.file[f].precomp[0]->sizetable = (uint16_t *)data;
data += size[6 * f + 1];
if (split) {
pawn.file[f].precomp[1]->sizetable = (uint16_t *)data;
data += size[6 * f + 4];
}
}
for (File f = FILE_A; f <= maxFile; ++f) {
data = (uint8_t *)(((uintptr_t)data + 0x3f) & ~0x3f);
pawn.file[f].precomp[0]->data = data;
data += size[6 * f + 2];
if (split) {
data = (uint8_t *)(((uintptr_t)data + 0x3f) & ~0x3f);
pawn.file[f].precomp[1]->data = data;
data += size[6 * f + 5];
}
}
}
return true;
}
bool DTZEntry::init(const std::string& fname)
{
uint8_t *next;
uint64_t tb_size[4];
uint64_t size[4 * 3];
uint8_t* data = TBFile(fname).map(&baseAddress, &mapping, TB_MAGIC);
if (!data)
return false;
File maxFile = *data & 2 ? FILE_D : FILE_A;
data++;
if (!has_pawns) {
int order = *data & 0xF;
data++;
for (int i = 0; i < num; ++i, ++data)
piece.pieces[i] = *data & 0x0F;
set_norms(piece, num);
tb_size[0] = set_factors(piece, num, order);
data += (uintptr_t)data & 1;
piece.precomp = setup_pairs(data, tb_size[0], &size[0], &next, &(piece.flags), 0);
data = next;
piece.map = data;
if (piece.flags & 2) {
int i;
for (i = 0; i < 4; ++i) {
piece.map_idx[i] = (uint16_t)(data + 1 - piece.map);
data += 1 + data[0];
}
data += (uintptr_t)data & 1;
}
piece.precomp->indextable = (char *)data;
data += size[0];
piece.precomp->sizetable = (uint16_t *)data;
data += size[1];
data = (uint8_t*)(((uintptr_t)data + 0x3F) & ~0x3F);
piece.precomp->data = data;
data += size[2];
} else {
bool p = (pawn.pawns[1] > 0);
for (File f = FILE_A; f <= FILE_D; ++f) {
int order1 = *data++ & 0xF;
int order2 = p ? *data++ & 0xF : 0xF;
for (int i = 0; i < num; ++i, ++data)
pawn.file[f].pieces[i] = *data & 0xF;
set_norm_pawn(pawn.pawns, pawn.file[f].norm, pawn.file[f].pieces, num);
tb_size[f] = calc_factors_pawn(pawn.file[f].factor, num, order1, order2, pawn.file[f].norm, f);
}
data += (uintptr_t)data & 1;
for (File f = FILE_A; f <= maxFile; ++f) {
pawn.file[f].precomp = setup_pairs(data, tb_size[f], &size[3 * f], &next, &(pawn.file[f].flags), 0);
data = next;
}
pawn.map = data;
for (File f = FILE_A; f <= maxFile; ++f) {
if (pawn.file[f].flags & 2)
for (int i = 0; i < 4; ++i) {
pawn.file[f].map_idx[i] = (uint16_t)(data + 1 - pawn.map);
data += 1 + data[0];
}
}
data += (uintptr_t)data & 1;
for (File f = FILE_A; f <= maxFile; ++f) {
pawn.file[f].precomp->indextable = (char *)data;
data += size[3 * f];
}
for (File f = FILE_A; f <= maxFile; ++f) {
pawn.file[f].precomp->sizetable = (uint16_t *)data;
data += size[3 * f + 1];
}
for (File f = FILE_A; f <= maxFile; ++f) {
data = (uint8_t *)(((uintptr_t)data + 0x3f) & ~0x3f);
pawn.file[f].precomp->data = data;
data += size[3 * f + 2];
}
}
return true;
}
template<typename T, int Half = sizeof(T)/2, int End = sizeof(T)-1>
inline void byteSwap(T& x)
{
char tmp, *c = (char*)(&x);
for (int i = 0; i < Half; ++i)
tmp = c[i], c[i] = c[End-i], c[End-i] = tmp;
}
int decompress_pairs(PairsData* d, uint64_t idx)
{
const union { uint32_t i; char c[4]; } LE = { 0x01020304 };
const bool LittleEndian = (LE.c[0] == 4);
if (!d->idxbits)
return d->min_len;
// idx = blockidx | litidx where litidx is a signed number of lenght d->idxbits
uint32_t blockidx = (uint32_t)(idx >> d->idxbits);
int litidx = (idx & ((1ULL << d->idxbits) - 1)) - (1ULL << (d->idxbits - 1));
// indextable points to an array of blocks of 6 bytes representing numbers in
// little endian. The low 4 bytes are the block, the high 2 bytes the idxOffset.
uint32_t block = *(uint32_t *)(d->indextable + 6 * blockidx);
uint16_t idxOffset = *(uint16_t *)(d->indextable + 6 * blockidx + 4);
if (!LittleEndian) {
byteSwap(block);
byteSwap(idxOffset);
}
litidx += idxOffset;
while (litidx < 0)
litidx += d->sizetable[--block] + 1;
while (litidx > d->sizetable[block])
litidx -= d->sizetable[block++] + 1;
uint32_t* ptr = (uint32_t*)(d->data + (block << d->blocksize));
uint64_t code = *((uint64_t*)ptr);
if (LittleEndian)
byteSwap(code);
int m = d->min_len;
uint16_t *offset = d->offset;
base_t* base = d->base - m;
uint8_t* symlen = d->symlen;
int sym, bitcnt;
ptr += 2;
bitcnt = 0; // number of "empty bits" in code
for (;;) {
int l = m;
while (code < base[l])
++l;
sym = offset[l];
if (!LittleEndian)
sym = ((sym & 0xff) << 8) | (sym >> 8);
sym += (int)((code - base[l]) >> (64 - l));
if (litidx < (int)symlen[sym] + 1)
break;
litidx -= (int)symlen[sym] + 1;
code <<= l;
bitcnt += l;
if (bitcnt >= 32) {
bitcnt -= 32;
uint32_t tmp = *ptr++;
if (LittleEndian)
byteSwap(tmp);
code |= (uint64_t)tmp << bitcnt;
}
}
uint8_t *sympat = d->sympat;
while (symlen[sym] != 0) {
uint8_t* w = sympat + (3 * sym);
int s1 = ((w[1] & 0xf) << 8) | w[0];
if (litidx < (int)symlen[s1] + 1)
sym = s1;
else {
litidx -= (int)symlen[s1] + 1;
sym = (w[2] << 4) | (w[1] >> 4);
}
}
return sympat[3 * sym];
}
WDLScore probe_wdl_table(Position& pos, int* success)
{
Key key = pos.material_key();
if (pos.count<ALL_PIECES>(WHITE) + pos.count<ALL_PIECES>(BLACK) == 2)
return WDLDraw; // KvK
WDLEntry* entry = WDLHash[key];
if (!entry) {
*success = 0;
return WDLDraw;
}
// Init table at first access attempt
if (!entry->ready) {
std::unique_lock<Mutex> lk(TB_mutex);
if (!entry->ready) {
std::string fname = file_name(pos, entry->key != key) + ".rtbw";
if (!entry->init(fname)) {
// Was ptr2->key = 0ULL; Just leave !ptr->ready condition
*success = 0;
return WDLDraw;
}
entry->ready = 1;
}
}
Square squares[TBPIECES];
int bside, smirror, cmirror;
assert(key == entry->key || !entry->symmetric);
// Entries are stored from point of view of white, so in case of a symmetric
// material distribution, we just need to lookup the relative TB entry in
// case we are black. Instead in case of asymmetric distribution, because
// stored entry is the same for both keys, we have first to verify if the
// entry is stored according to our key, otherwise we have to lookup
// the relative entry.
if (entry->symmetric) {
cmirror = pos.side_to_move() * 8;
smirror = pos.side_to_move() * 070;
bside = WHITE;
} else {
cmirror = (key != entry->key) * 8; // Switch color
smirror = (key != entry->key) * 070; // Vertical flip SQ_A1 -> SQ_A8
bside = (key != entry->key) ^ pos.side_to_move();
}
// squares[i] is to contain the square 0-63 (A1-H8) for a piece of type
// pc[i] ^ cmirror, where 1 = white pawn, ..., 14 = black king.
// Pieces of the same type are guaranteed to be consecutive.
if (!entry->has_pawns) {
for (int i = 0; i < entry->num; ) {
Piece pc = Piece(entry->piece[bside].pieces[i] ^ cmirror);
Bitboard b = pos.pieces(color_of(pc), type_of(pc));
do
squares[i++] = pop_lsb(&b);
while (b);
}
uint64_t idx = encode_piece(entry->piece[bside].hasUniquePieces, entry->piece[bside].norm, squares, entry->piece[bside].factor, entry->num);
return WDLScore(decompress_pairs(entry->piece[bside].precomp, idx) - 2);
} else {
Piece pc = Piece(entry->pawn.file[0].pieces[0][0] ^ cmirror);
Bitboard b = pos.pieces(color_of(pc), type_of(pc));
int i = 0;
do
squares[i++] = pop_lsb(&b) ^ smirror;
while (b);
File f = pawn_file(entry->pawn.pawns, squares);
for ( ; i < entry->num; ) {
pc = Piece(entry->pawn.file[f].pieces[bside][i] ^ cmirror);
b = pos.pieces(color_of(pc), type_of(pc));
do
squares[i++] = pop_lsb(&b) ^ smirror;
while (b);
}
uint64_t idx = encode_pawn(entry->pawn.pawns, entry->pawn.file[f].norm[bside], squares, entry->pawn.file[f].factor[bside], entry->num);
return WDLScore(decompress_pairs(entry->pawn.file[f].precomp[bside], idx) - 2);
}
}
int probe_dtz_table(const Position& pos, int wdl, int *success)
{
Key key = pos.material_key();
if ( DTZTable.front().keys[0] != key
&& DTZTable.front().keys[1] != key) {
// Enforce "Most Recently Used" (MRU) order for DTZ_list
for (auto it = DTZTable.begin(); it != DTZTable.end(); ++it)
if (it->keys[0] == key) {
// Move to front without deleting the element
DTZTable.splice(DTZTable.begin(),DTZTable, it);
break;
}
// If still not found, add a new one
if (DTZTable.front().keys[0] != key) {
WDLEntry* ptr = WDLHash[key];
if (!ptr) {
*success = 0;
return 0;
}
StateInfo st;
Position p;
std::string code = file_name(pos, ptr->key != key);
std::string fname = code + ".rtbz";
code.erase(code.find('v'), 1);
Key keys[] = { p.set(code, WHITE, &st).material_key(),
p.set(code, BLACK, &st).material_key() };
DTZTable.push_front(DTZEntry(*ptr, keys));
if (!DTZTable.front().init(fname)) {
// In case file is not found init() fails, but we leave
// the entry so to avoid rechecking at every probe (same
// functionality as WDL case).
// FIXME: This is different form original functionality!
/* DTZTable.pop_front(); */
*success = 0;
return 0;
}
// Keep list size within 64 entries
// FIXME remove it when we will know what we are doing
if (DTZTable.size() > 64)
DTZTable.pop_back();
}
}
DTZEntry* ptr = &DTZTable.front();
if (!ptr->baseAddress) {
*success = 0;
return 0;
}
uint64_t idx;
int i, res;
Square squares[TBPIECES];
int bside, mirror, cmirror;
if (!ptr->symmetric) {
if (key != ptr->key) {
cmirror = 8;
mirror = 070;
bside = (pos.side_to_move() == WHITE);
} else {
cmirror = mirror = 0;
bside = !(pos.side_to_move() == WHITE);
}
} else {
cmirror = pos.side_to_move() == WHITE ? 0 : 8;
mirror = pos.side_to_move() == WHITE ? 0 : 070;
bside = 0;
}
if (!ptr->has_pawns) {
if ((ptr->piece.flags & 1) != bside && !ptr->symmetric) {
*success = -1;
return 0;
}
uint8_t *pc = ptr->piece.pieces;
for (i = 0; i < ptr->num;) {
Bitboard bb = pos.pieces((Color)((pc[i] ^ cmirror) >> 3),
(PieceType)(pc[i] & 7));
do {
squares[i++] = pop_lsb(&bb);
} while (bb);
}
idx = encode_piece(ptr->piece.hasUniquePieces, ptr->piece.norm, squares, ptr->piece.factor, ptr->num);
res = decompress_pairs(ptr->piece.precomp, idx);
if (ptr->piece.flags & 2)
res = ptr->piece.map[ptr->piece.map_idx[wdl_to_map[wdl + 2]] + res];
if (!(ptr->piece.flags & pa_flags[wdl + 2]) || (wdl & 1))
res *= 2;
} else {
int k = ptr->pawn.file[0].pieces[0] ^ cmirror;
Bitboard bb = pos.pieces((Color)(k >> 3), (PieceType)(k & 7));
i = 0;
do {
squares[i++] = pop_lsb(&bb) ^ mirror;
} while (bb);
File f = pawn_file(ptr->pawn.pawns, squares);
if ((ptr->pawn.file[f].flags & 1) != bside) {
*success = -1;
return 0;
}
uint8_t *pc = ptr->pawn.file[f].pieces;
for (; i < ptr->num;) {
bb = pos.pieces((Color)((pc[i] ^ cmirror) >> 3),
(PieceType)(pc[i] & 7));
do {
squares[i++] = pop_lsb(&bb) ^ mirror;
} while (bb);
}
idx = encode_pawn(ptr->pawn.pawns, ptr->pawn.file[f].norm, squares, ptr->pawn.file[f].factor, ptr->num);
res = decompress_pairs(ptr->pawn.file[f].precomp, idx);
if (ptr->pawn.file[f].flags & 2)
res = ptr->pawn.map[ptr->pawn.file[f].map_idx[wdl_to_map[wdl + 2]] + res];
if (!(ptr->pawn.file[f].flags & pa_flags[wdl + 2]) || (wdl & 1))
res *= 2;
}
return res;
}
// Add underpromotion captures to list of captures.
ExtMove *add_underprom_caps(Position& pos, ExtMove *stack, ExtMove *end)
{
ExtMove *moves, *extra = end;
for (moves = stack; moves < end; ++moves) {
Move move = moves->move;
if (type_of(move) == PROMOTION && !pos.empty(to_sq(move))) {
(*extra++).move = (Move)(move - (1 << 12));
(*extra++).move = (Move)(move - (2 << 12));
(*extra++).move = (Move)(move - (3 << 12));
}
}
return extra;
}
WDLScore probe_ab(Position& pos, WDLScore alpha, WDLScore beta, int *success)
{
WDLScore value;
ExtMove stack[64];
ExtMove *moves, *end;
StateInfo st;
// Generate (at least) all legal non-ep captures including (under)promotions.
// It is OK to generate more, as long as they are filtered out below.
if (!pos.checkers()) {
end = generate<CAPTURES>(pos, stack);
// Since underpromotion captures are not included, we need to add them.
end = add_underprom_caps(pos, stack, end);
} else
end = generate<EVASIONS>(pos, stack);
CheckInfo ci(pos);
for (moves = stack; moves < end; ++moves) {
Move capture = moves->move;
if ( !pos.capture(capture)
|| type_of(capture) == ENPASSANT
|| !pos.legal(capture, ci.pinned))
continue;
pos.do_move(capture, st, pos.gives_check(capture, ci));
value = -probe_ab(pos, -beta, -alpha, success);
pos.undo_move(capture);
if (*success == 0)
return WDLDraw;
if (value > alpha) {
if (value >= beta) {
*success = 2;
return value;
}
alpha = value;
}
}
value = probe_wdl_table(pos, success); // FIXME why this is not at the beginning?
if (*success == 0)
return WDLDraw;
if (alpha >= value) {
*success = 1 + (alpha > 0);
return alpha;
} else {
*success = 1;
return value;
}
}
int probe_dtz(Position& pos, int *success);
// This routine treats a position with en passant captures as one without.
int probe_dtz_no_ep(Position& pos, int *success)
{
int dtz;
WDLScore wdl = probe_ab(pos, WDLHardLoss, WDLHardWin, success);
if (*success == 0) return 0;
if (wdl == WDLDraw) return 0;
if (*success == 2)
return wdl == WDLHardWin ? 1 : 101;
ExtMove stack[MAX_MOVES];
ExtMove *moves, *end = nullptr;
StateInfo st;
CheckInfo ci(pos);
if (wdl > 0) {
// Generate at least all legal non-capturing pawn moves
// including non-capturing promotions.
if (!pos.checkers())
end = generate<NON_EVASIONS>(pos, stack);
else
end = generate<EVASIONS>(pos, stack);
for (moves = stack; moves < end; ++moves) {
Move move = moves->move;
if ( type_of(pos.moved_piece(move)) != PAWN
|| pos.capture(move)
|| !pos.legal(move, ci.pinned))
continue;
pos.do_move(move, st, pos.gives_check(move, ci));
WDLScore v = -probe_ab(pos, WDLHardLoss, -wdl + WDLSoftWin, success);
pos.undo_move(move);
if (*success == 0) return 0;
if (v == wdl)
return v == WDLHardWin ? 1 : 101;
}
}
dtz = 1 + probe_dtz_table(pos, wdl, success);
if (*success >= 0) {
if (wdl & 1) dtz += 100;
return wdl >= 0 ? dtz : -dtz;
}
if (wdl > 0) {
int best = 0xffff;
for (moves = stack; moves < end; ++moves) {
Move move = moves->move;
if (pos.capture(move) || type_of(pos.moved_piece(move)) == PAWN
|| !pos.legal(move, ci.pinned))
continue;
pos.do_move(move, st, pos.gives_check(move, ci));
int v = -probe_dtz(pos, success);
pos.undo_move(move);
if (*success == 0)
return 0;
if (v > 0 && v + 1 < best)
best = v + 1;
}
return best;
} else {
int best = -1;
if (!pos.checkers())
end = generate<NON_EVASIONS>(pos, stack);
else
end = generate<EVASIONS>(pos, stack);
for (moves = stack; moves < end; ++moves) {
int v;
Move move = moves->move;
if (!pos.legal(move, ci.pinned))
continue;
pos.do_move(move, st, pos.gives_check(move, ci));
if (st.rule50 == 0) {
if (wdl == -2) v = -1;
else {
v = probe_ab(pos, WDLSoftWin, WDLHardWin, success);
v = (v == 2) ? 0 : -101;
}
} else {
v = -probe_dtz(pos, success) - 1;
}
pos.undo_move(move);
if (*success == 0)
return 0;
if (v < best)
best = v;
}
return best;
}
}
// Probe the DTZ table for a particular position.
// If *success != 0, the probe was successful.
// The return value is from the point of view of the side to move:
// n < -100 : loss, but draw under 50-move rule
// -100 <= n < -1 : loss in n ply (assuming 50-move counter == 0)
// 0 : draw
// 1 < n <= 100 : win in n ply (assuming 50-move counter == 0)
// 100 < n : win, but draw under 50-move rule
//
// The return value n can be off by 1: a return value -n can mean a loss
// in n+1 ply and a return value +n can mean a win in n+1 ply. This
// cannot happen for tables with positions exactly on the "edge" of
// the 50-move rule.
//
// This implies that if dtz > 0 is returned, the position is certainly
// a win if dtz + 50-move-counter <= 99. Care must be taken that the engine
// picks moves that preserve dtz + 50-move-counter <= 99.
//
// If n = 100 immediately after a capture or pawn move, then the position
// is also certainly a win, and during the whole phase until the next
// capture or pawn move, the inequality to be preserved is
// dtz + 50-movecounter <= 100.
//
// In short, if a move is available resulting in dtz + 50-move-counter <= 99,
// then do not accept moves leading to dtz + 50-move-counter == 100.
//
int probe_dtz(Position& pos, int *success)
{
*success = 1;
int v = probe_dtz_no_ep(pos, success);
if (pos.ep_square() == SQ_NONE)
return v;
if (*success == 0)
return 0;
// Now handle en passant.
int v1 = -3;
ExtMove stack[MAX_MOVES];
ExtMove *moves, *end;
StateInfo st;
if (!pos.checkers())
end = generate<CAPTURES>(pos, stack);
else
end = generate<EVASIONS>(pos, stack);
CheckInfo ci(pos);
for (moves = stack; moves < end; ++moves) {
Move capture = moves->move;
if (type_of(capture) != ENPASSANT
|| !pos.legal(capture, ci.pinned))
continue;
pos.do_move(capture, st, pos.gives_check(capture, ci));
WDLScore v0 = -probe_ab(pos, WDLHardLoss, WDLHardWin, success);
pos.undo_move(capture);
if (*success == 0)
return 0;
if (v0 > v1) v1 = v0;
}
if (v1 > -3) {
v1 = wdl_to_dtz[v1 + 2];
if (v < -100) {
if (v1 >= 0)
v = v1;
} else if (v < 0) {
if (v1 >= 0 || v1 < -100)
v = v1;
} else if (v > 100) {
if (v1 > 0)
v = v1;
} else if (v > 0) {
if (v1 == 1)
v = v1;
} else if (v1 >= 0) {
v = v1;
} else {
for (moves = stack; moves < end; ++moves) {
Move move = moves->move;
if (type_of(move) == ENPASSANT) continue;
if (pos.legal(move, ci.pinned))
break;
}
if (moves == end && !pos.checkers()) {
end = generate<QUIETS>(pos, end);
for (; moves < end; ++moves) {
Move move = moves->move;
if (pos.legal(move, ci.pinned))
break;
}
}
if (moves == end)
v = v1;
}
}
return v;
}
} // namespace
void Tablebases::init(const std::string& paths)
{
DTZTable.clear();
WDLTable.clear();
WDLHash.clear();
MaxCardinality = 0;
TBPaths = paths;
if (TBPaths.empty() || TBPaths == "<empty>")
return;
// Fill binomial[] with the Binomial Coefficents using Pascal triangle
Binomial[0][0] = 1;
for (int n = 1; n < 64; n++)
for (int k = 0; k < 6 && k <= n; ++k)
Binomial[k][n] = (k > 0 ? Binomial[k-1][n-1] : 0)
+ (k < n ? Binomial[k][n-1] : 0);
for (int i = 0; i < 5; ++i) {
int k = 0;
for (int j = 1; j <= 4; ++j) {
int s = 0;
for ( ; k < 6 * j; ++k) {
Pawnidx[i][k] = s;
s += Binomial[i][Ptwist[Invflap[k]]];
}
Pfactor[i][j - 1] = s;
}
}
for (PieceType p1 = PAWN; p1 < KING; ++p1) {
WDLHash.insert({KING, p1, KING});
for (PieceType p2 = PAWN; p2 <= p1; ++p2) {
WDLHash.insert({KING, p1, p2, KING});
WDLHash.insert({KING, p1, KING, p2});
for (PieceType p3 = PAWN; p3 < KING; ++p3)
WDLHash.insert({KING, p1, p2, KING, p3});
for (PieceType p3 = PAWN; p3 <= p2; ++p3) {
WDLHash.insert({KING, p1, p2, p3, KING});
for (PieceType p4 = PAWN; p4 <= p3; ++p4)
WDLHash.insert({KING, p1, p2, p3, p4, KING});
for (PieceType p4 = PAWN; p4 < KING; ++p4)
WDLHash.insert({KING, p1, p2, p3, KING, p4});
}
for (PieceType p3 = PAWN; p3 <= p1; ++p3)
for (PieceType p4 = PAWN; p4 <= (p1 == p3 ? p2 : p3); ++p4)
WDLHash.insert({KING, p1, p2, KING, p3, p4});
}
}
std::cerr << "info string Found " << WDLTable.size() << " tablebases" << std::endl;
}
// Probe the WDL table for a particular position.
// If *success != 0, the probe was successful.
// The return value is from the point of view of the side to move:
// -2 : loss
// -1 : loss, but draw under 50-move rule
// 0 : draw
// 1 : win, but draw under 50-move rule
// 2 : win
WDLScore Tablebases::probe_wdl(Position& pos, int *success)
{
*success = 1;
WDLScore v = probe_ab(pos, WDLHardLoss, WDLHardWin, success);
// If en passant is not possible, we are done.
if (pos.ep_square() == SQ_NONE)
return v;
if (*success == 0)
return WDLDraw;
// Now handle en passant.
WDLScore v1 = WDLScore(-3); // FIXME use a proper enum value here
// Generate (at least) all legal en passant captures.
ExtMove stack[MAX_MOVES];
ExtMove *moves, *end;
StateInfo st;
if (!pos.checkers())
end = generate<CAPTURES>(pos, stack);
else
end = generate<EVASIONS>(pos, stack);
CheckInfo ci(pos);
for (moves = stack; moves < end; ++moves) {
Move capture = moves->move;
if (type_of(capture) != ENPASSANT
|| !pos.legal(capture, ci.pinned))
continue;
pos.do_move(capture, st, pos.gives_check(capture, ci));
WDLScore v0 = -probe_ab(pos, WDLHardLoss, WDLHardWin, success);
pos.undo_move(capture);
if (*success == 0)
return WDLDraw;
if (v0 > v1) v1 = v0;
}
if (v1 > -3) {
if (v1 >= v) v = v1;
else if (v == 0) {
// Check whether there is at least one legal non-ep move.
for (moves = stack; moves < end; ++moves) {
Move capture = moves->move;
if (type_of(capture) == ENPASSANT) continue;
if (pos.legal(capture, ci.pinned))
break;
}
if (moves == end && !pos.checkers()) {
end = generate<QUIETS>(pos, end);
for (; moves < end; ++moves) {
Move move = moves->move;
if (pos.legal(move, ci.pinned))
break;
}
}
// If not, then we are forced to play the losing ep capture.
if (moves == end)
v = v1;
}
}
return v;
}
// Check whether there has been at least one repetition of positions
// since the last capture or pawn move.
static int has_repeated(StateInfo *st)
{
while (1) {
int i = 4, e = std::min(st->rule50, st->pliesFromNull);
if (e < i)
return 0;
StateInfo *stp = st->previous->previous;
do {
stp = stp->previous->previous;
if (stp->key == st->key)
return 1;
i += 2;
} while (i <= e);
st = st->previous;
}
}
// Use the DTZ tables to filter out moves that don't preserve the win or draw.
// If the position is lost, but DTZ is fairly high, only keep moves that
// maximise DTZ.
//
// A return value false indicates that not all probes were successful and that
// no moves were filtered out.
bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves, Value& score)
{
int success;
int dtz = probe_dtz(pos, &success);
if (!success)
return false;
StateInfo st;
CheckInfo ci(pos);
// Probe each move
for (size_t i = 0; i < rootMoves.size(); ++i) {
Move move = rootMoves[i].pv[0];
pos.do_move(move, st, pos.gives_check(move, ci));
int v = 0;
if (pos.checkers() && dtz > 0) {
ExtMove s[MAX_MOVES];
if (generate<LEGAL>(pos, s) == s)
v = 1;
}
if (!v) {
if (st.rule50 != 0) {
v = -probe_dtz(pos, &success);
if (v > 0)
++v;
else if (v < 0)
--v;
} else {
v = -probe_wdl(pos, &success);
v = wdl_to_dtz[v + 2];
}
}
pos.undo_move(move);
if (!success)
return false;
rootMoves[i].score = (Value)v;
}
// Obtain 50-move counter for the root position.
// In Stockfish there seems to be no clean way, so we do it like this:
int cnt50 = st.previous->rule50;
// Use 50-move counter to determine whether the root position is
// won, lost or drawn.
int wdl = 0;
if (dtz > 0)
wdl = (dtz + cnt50 <= 100) ? 2 : 1;
else if (dtz < 0)
wdl = (-dtz + cnt50 <= 100) ? -2 : -1;
// Determine the score to report to the user.
score = WDL_to_value[wdl + 2];
// If the position is winning or losing, but too few moves left, adjust the
// score to show how close it is to winning or losing.
// NOTE: int(PawnValueEg) is used as scaling factor in score_to_uci().
if (wdl == 1 && dtz <= 100)
score = (Value)(((200 - dtz - cnt50) * int(PawnValueEg)) / 200);
else if (wdl == -1 && dtz >= -100)
score = -(Value)(((200 + dtz - cnt50) * int(PawnValueEg)) / 200);
// Now be a bit smart about filtering out moves.
size_t j = 0;
if (dtz > 0) { // winning (or 50-move rule draw)
int best = 0xffff;
for (size_t i = 0; i < rootMoves.size(); ++i) {
int v = rootMoves[i].score;
if (v > 0 && v < best)
best = v;
}
int max = best;
// If the current phase has not seen repetitions, then try all moves
// that stay safely within the 50-move budget, if there are any.
if (!has_repeated(st.previous) && best + cnt50 <= 99)
max = 99 - cnt50;
for (size_t i = 0; i < rootMoves.size(); ++i) {
int v = rootMoves[i].score;
if (v > 0 && v <= max)
rootMoves[j++] = rootMoves[i];
}
} else if (dtz < 0) { // losing (or 50-move rule draw)
int best = 0;
for (size_t i = 0; i < rootMoves.size(); ++i) {
int v = rootMoves[i].score;
if (v < best)
best = v;
}
// Try all moves, unless we approach or have a 50-move rule draw.
if (-best * 2 + cnt50 < 100)
return true;
for (size_t i = 0; i < rootMoves.size(); ++i) {
if (rootMoves[i].score == best)
rootMoves[j++] = rootMoves[i];
}
} else { // drawing
// Try all moves that preserve the draw.
for (size_t i = 0; i < rootMoves.size(); ++i) {
if (rootMoves[i].score == 0)
rootMoves[j++] = rootMoves[i];
}
}
rootMoves.resize(j, Search::RootMove(MOVE_NONE));
return true;
}
// Use the WDL tables to filter out moves that don't preserve the win or draw.
// This is a fallback for the case that some or all DTZ tables are missing.
//
// A return value false indicates that not all probes were successful and that
// no moves were filtered out.
bool Tablebases::root_probe_wdl(Position& pos, Search::RootMoves& rootMoves, Value& score)
{
int success;
WDLScore wdl = Tablebases::probe_wdl(pos, &success);
if (!success)
return false;
score = WDL_to_value[wdl + 2];
StateInfo st;
CheckInfo ci(pos);
int best = WDLHardLoss;
// Probe each move
for (size_t i = 0; i < rootMoves.size(); ++i) {
Move move = rootMoves[i].pv[0];
pos.do_move(move, st, pos.gives_check(move, ci));
WDLScore v = -Tablebases::probe_wdl(pos, &success);
pos.undo_move(move);
if (!success)
return false;
rootMoves[i].score = (Value)v;
if (v > best)
best = v;
}
size_t j = 0;
for (size_t i = 0; i < rootMoves.size(); ++i) {
if (rootMoves[i].score == best)
rootMoves[j++] = rootMoves[i];
}
rootMoves.resize(j, Search::RootMove(MOVE_NONE));
return true;
}
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