/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
/*
The code in this file is based on the opening book code in PolyGlot
- by Fabien Letouzey. PolyGlot is available under the GNU General
+ by Fabien Letouzey. PolyGlot is available under the GNU General
Public License, and can be downloaded from http://wbec-ridderkerk.nl
*/
-
-////
-//// Includes
-////
-
#include <cassert>
+#include <iostream>
#include "book.h"
-#include "mersenne.h"
+#include "misc.h"
#include "movegen.h"
using namespace std;
-////
-//// Global variables
-////
-
-Book OpeningBook;
-
-
-////
-//// Local definitions
-////
-
namespace {
- /// Book entry size in bytes
- const int EntrySize = 16;
-
-
- /// Random numbers from PolyGlot, used to compute book hash keys
-
- const uint64_t Random64[781] = {
+ // Random numbers from PolyGlot, used to compute book hash keys
+ const Key PolyGlotRandoms[781] = {
0x9D39247E33776D41ULL, 0x2AF7398005AAA5C7ULL, 0x44DB015024623547ULL,
0x9C15F73E62A76AE2ULL, 0x75834465489C0C89ULL, 0x3290AC3A203001BFULL,
0x0FBBAD1F61042279ULL, 0xE83A908FF2FB60CAULL, 0x0D7E765D58755C10ULL,
0xF8D626AAAF278509ULL
};
+ // Offsets to the PolyGlotRandoms[] array of zobrist keys
+ const Key* ZobPiece = PolyGlotRandoms + 0;
+ const Key* ZobCastle = PolyGlotRandoms + 768;
+ const Key* ZobEnPassant = PolyGlotRandoms + 772;
+ const Key* ZobTurn = PolyGlotRandoms + 780;
- /// Indices to the Random64[] array
+ // Piece offset is calculated as 64 * (PolyPiece ^ 1) where
+ // PolyPiece is: BP = 0, WP = 1, BN = 2, WN = 3 ... BK = 10, WK = 11
+ const int PieceOfs[] = { 0, 64, 192, 320, 448, 576, 704, 0,
+ 0, 0, 128, 256, 384, 512, 640 };
- const int RandomPiece = 0;
- const int RandomCastle = 768;
- const int RandomEnPassant = 772;
- const int RandomTurn = 780;
+ // book_key() builds up a PolyGlot hash key out of a position
+ uint64_t book_key(const Position& pos) {
+ uint64_t result = 0;
+ Bitboard b = pos.occupied_squares();
- /// Prototypes
+ while (b)
+ {
+ Square s = pop_1st_bit(&b);
+ result ^= ZobPiece[PieceOfs[pos.piece_on(s)] + s];
+ }
- uint64_t book_key(const Position& pos);
- uint64_t book_piece_key(Piece p, Square s);
- uint64_t book_castle_key(const Position& pos);
- uint64_t book_ep_key(const Position& pos);
- uint64_t book_color_key(const Position& pos);
-}
+ if (pos.can_castle(WHITE_OO))
+ result ^= ZobCastle[0];
+ if (pos.can_castle(WHITE_OOO))
+ result ^= ZobCastle[1];
-////
-//// Functions
-////
+ if (pos.can_castle(BLACK_OO))
+ result ^= ZobCastle[2];
+ if (pos.can_castle(BLACK_OOO))
+ result ^= ZobCastle[3];
-/// Destructor. Be sure file is closed before we leave.
+ if (pos.ep_square() != SQ_NONE)
+ result ^= ZobEnPassant[file_of(pos.ep_square())];
-Book::~Book() {
+ if (pos.side_to_move() == WHITE)
+ result ^= ZobTurn[0];
- close();
+ return result;
+ }
}
-/// Book::open() opens a book file with a given file name
+/// Book c'tor. Make random number generation less deterministic, for book moves
+Book::Book() : bookSize(0) {
-void Book::open(const string& fName) {
+ for (int i = abs(system_time() % 10000); i > 0; i--)
+ RKiss.rand<unsigned>();
+}
- // Close old file before opening the new
- close();
- fileName = fName;
- ifstream::open(fileName.c_str(), ifstream::in | ifstream::binary);
- if (!is_open())
- return;
+/// Book destructor. Be sure file is closed before we leave.
- // Get the book size in number of entries
- seekg(0, ios::end);
- bookSize = tellg() / EntrySize;
- seekg(0, ios::beg);
+Book::~Book() {
- if (!good())
- {
- cerr << "Failed to open book file " << fileName << endl;
- Application::exit_with_failure();
- }
+ close();
}
-/// Book::close() closes the file only if it is open, otherwise
-/// we can end up in a little mess due to how std::ifstream works.
+/// Book::close() closes the file only if it is open, otherwise the call fails
+/// and the failbit internal state flag is set.
void Book::close() {
- if (is_open())
- ifstream::close();
+ if (bookFile.is_open())
+ bookFile.close();
+
+ bookName = "";
+ bookSize = 0;
}
-/// Book::file_name() returns the file name of the currently active book,
-/// or the empty string if no book is open.
+/// Book::open() opens a book file with a given name
+
+void Book::open(const string& fileName) {
-const string Book::file_name() const {
+ // Close old file before opening the new
+ close();
+
+ bookFile.open(fileName.c_str(), ifstream::in | ifstream::binary |ios::ate);
+
+ // Silently return when asked to open a non-exsistent file
+ if (!bookFile.is_open())
+ return;
- return is_open() ? fileName : "";
+ // Get the book size in number of entries, we are already at the file end
+ bookSize = long(bookFile.tellg()) / sizeof(BookEntry);
+
+ if (!bookFile.good())
+ {
+ cerr << "Failed to open book file " << fileName << endl;
+ exit(EXIT_FAILURE);
+ }
+
+ // Set only if successful
+ bookName = fileName;
}
-/// Book::get_move() gets a book move for a given position. Returns
-/// MOVE_NONE if no book move is found.
+/// Book::probe() gets a book move for a given position. Returns MOVE_NONE
+/// if no book move is found. If findBest is true then returns always the
+/// highest rated move otherwise chooses randomly based on the move score.
-Move Book::get_move(const Position& pos) {
+Move Book::probe(const Position& pos, bool findBest) {
- if (!is_open() || bookSize == 0)
+ if (!bookSize || !bookFile.is_open())
return MOVE_NONE;
- int bookMove = 0, scoresSum = 0;
- uint64_t key = book_key(pos);
BookEntry entry;
+ unsigned scoresSum = 0, bestScore = 0, bookMove = 0;
+ uint64_t key = book_key(pos);
+ int idx = first_entry(key) - 1;
// Choose a book move among the possible moves for the given position
- for (int idx = find_key(key); idx < bookSize; idx++)
+ while (++idx < bookSize && (entry = read_entry(idx), entry.key == key))
{
- read_entry(entry, idx);
- if (entry.key != key)
- break;
-
- int score = entry.count;
-
- assert(score > 0);
+ scoresSum += entry.count;
// Choose book move according to its score. If a move has a very
- // high score it has more probability to be choosen then a one with
- // lower score. Note that first entry is always chosen.
- scoresSum += score;
- if (int(genrand_int32() % scoresSum) < score)
+ // high score it has higher probability to be choosen than a move
+ // with lower score. Note that first entry is always chosen.
+ if ( RKiss.rand<unsigned>() % scoresSum < entry.count
+ || (findBest && entry.count > bestScore))
bookMove = entry.move;
+
+ if (entry.count > bestScore)
+ bestScore = entry.count;
}
+
if (!bookMove)
return MOVE_NONE;
- MoveStack mlist[256];
- MoveStack* last = generate_moves(pos, mlist);
- for (MoveStack* cur = mlist; cur != last; cur++)
- if ((int(cur->move) & 07777) == bookMove)
- return cur->move;
+ // A PolyGlot book move is encoded as follows:
+ //
+ // bit 0- 5: destination square (from 0 to 63)
+ // bit 6-11: origin square (from 0 to 63)
+ // bit 12-13-14: promotion piece (from KNIGHT == 1 to QUEEN == 4)
+ //
+ // Castling moves follow "king captures rook" representation. So in case
+ // book move is a promotion we have to convert to our representation, in
+ // all other cases we can directly compare with a Move after having
+ // masked out special Move's flags that are not supported by PolyGlot.
+ int promotion = (bookMove >> 12) & 7;
+
+ if (promotion)
+ bookMove = make_promotion_move(move_from(Move(bookMove)),
+ move_to(Move(bookMove)),
+ PieceType(promotion + 1));
+ // Verify the book move is legal
+ for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
+ if (unsigned(ml.move() & ~(3 << 14)) == bookMove) // Mask out special flags
+ return ml.move();
return MOVE_NONE;
}
-/// Book::find_key() takes a book key as input, and does a binary search
-/// through the book file for the given key. The index to the first book
-/// entry with the same key as the input is returned. When the key is not
+/// Book::first_entry() takes a book key as input, and does a binary search
+/// through the book file for the given key. The index to the first (leftmost)
+/// book entry with the same key as the input is returned. When the key is not
/// found in the book file, bookSize is returned.
-int Book::find_key(uint64_t key) {
+int Book::first_entry(uint64_t key) {
int left, right, mid;
- BookEntry entry;
- // Binary search (finds the leftmost entry)
+ // Binary search (finds the leftmost entry with given key)
left = 0;
right = bookSize - 1;
assert(mid >= left && mid < right);
- read_entry(entry, mid);
- if (key <= entry.key)
+ if (key <= read_entry(mid).key)
right = mid;
else
left = mid + 1;
assert(left == right);
- read_entry(entry, left);
- return (entry.key == key)? left : bookSize;
-}
-
-
-/// Book::read_entry() takes a BookEntry reference and an integer index as
-/// input, and looks up the opening book entry at the given index in the book
-/// file. The book entry is copied to the first input parameter.
-
-void Book::read_entry(BookEntry& entry, int idx) {
-
- assert(idx >= 0 && idx < bookSize);
- assert(is_open());
-
- seekg(idx * EntrySize, ios_base::beg);
- *this >> entry;
- if (!good())
- {
- cerr << "Failed to read book entry at index " << idx << endl;
- Application::exit_with_failure();
- }
+ return read_entry(left).key == key ? left : bookSize;
}
-/// Book::read_integer() reads size chars from the file stream
-/// and converts them in an integer number.
-
-uint64_t Book::read_integer(int size) {
+/// Book::operator>>() reads sizeof(T) chars from the file's binary byte
+/// stream and converts them in a number of type T.
+template<typename T>
+Book& Book::operator>>(T& n) {
- char buf[8];
- read(buf, size);
+ n = 0;
- // Numbers are stored on disk as a binary byte stream
- uint64_t n = 0ULL;
- for (int i = 0; i < size; i++)
- n = (n << 8) + (unsigned char)buf[i];
+ for (size_t i = 0; i < sizeof(T); i++)
+ n = T((n << 8) + bookFile.get());
- return n;
+ return *this;
}
-////
-//// Local definitions
-////
-
-namespace {
-
- uint64_t book_key(const Position& pos) {
+/// Book::read_entry() takes an integer index, and returns the BookEntry
+/// at the given index in the book file.
- uint64_t result = 0ULL;
+BookEntry Book::read_entry(int idx) {
- for (Color c = WHITE; c <= BLACK; c++)
- {
- Bitboard b = pos.pieces_of_color(c);
-
- while (b)
- {
- Square s = pop_1st_bit(&b);
- Piece p = pos.piece_on(s);
-
- assert(piece_is_ok(p));
- assert(color_of_piece(p) == c);
-
- result ^= book_piece_key(p, s);
- }
- }
- result ^= book_castle_key(pos);
- result ^= book_ep_key(pos);
- result ^= book_color_key(pos);
- return result;
- }
-
-
- uint64_t book_piece_key(Piece p, Square s) {
-
- /// Convert pieces to the range 0..11
- static const int PieceTo12[] = { 0, 0, 2, 4, 6, 8, 10, 0, 0, 1, 3, 5, 7, 9, 11 };
-
- return Random64[RandomPiece + (PieceTo12[int(p)]^1) * 64 + int(s)];
- }
-
-
- uint64_t book_castle_key(const Position& pos) {
-
- uint64_t result = 0ULL;
-
- if (pos.can_castle_kingside(WHITE))
- result ^= Random64[RandomCastle+0];
-
- if (pos.can_castle_queenside(WHITE))
- result ^= Random64[RandomCastle+1];
-
- if (pos.can_castle_kingside(BLACK))
- result ^= Random64[RandomCastle+2];
-
- if (pos.can_castle_queenside(BLACK))
- result ^= Random64[RandomCastle+3];
-
- return result;
- }
+ assert(idx >= 0 && idx < bookSize);
+ assert(bookFile.is_open());
+ BookEntry e;
- uint64_t book_ep_key(const Position& pos) {
- return (pos.ep_square() == SQ_NONE ? 0ULL : Random64[RandomEnPassant + square_file(pos.ep_square())]);
- }
+ bookFile.seekg(idx * sizeof(BookEntry), ios_base::beg);
+ *this >> e.key >> e.move >> e.count >> e.learn;
- uint64_t book_color_key(const Position& pos) {
- return (pos.side_to_move() == WHITE ? Random64[RandomTurn] : 0ULL);
+ if (!bookFile.good())
+ {
+ cerr << "Failed to read book entry at index " << idx << endl;
+ exit(EXIT_FAILURE);
}
+ return e;
}
projects / stockfish / blobdiff