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Small touches to book.cpp

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No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2011-10-03 08:02:46 +01:00
parent c2c185423b
commit 80dd90f972
3 changed files with 27 additions and 38 deletions
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61
src/book.cpp
View File

@@ -361,8 +361,8 @@ Book::~Book() {
} }
/// Book::close() closes the file only if it is open, otherwise /// Book::close() closes the file only if it is open, otherwise the call fails
/// we can end up in a little mess due to how std::ifstream works. /// and the failbit internal state flag is set.
void Book::close() { void Book::close() {
@@ -374,21 +374,20 @@ void Book::close() {
} }
/// Book::open() opens a book file with a given file name /// Book::open() opens a book file with a given name
void Book::open(const string& fileName) { void Book::open(const string& fileName) {
// Close old file before opening the new // Close old file before opening the new
close(); close();
bookFile.open(fileName.c_str(), ifstream::in | ifstream::binary); bookFile.open(fileName.c_str(), ifstream::in | ifstream::binary |ios::ate);
// Silently return when asked to open a non-exsistent file // Silently return when asked to open a non-exsistent file
if (!bookFile.is_open()) if (!bookFile.is_open())
return; return;
// Get the book size in number of entries // Get the book size in number of entries, we are already at the file end
bookFile.seekg(0, ios::end);
bookSize = long(bookFile.tellg()) / sizeof(BookEntry); bookSize = long(bookFile.tellg()) / sizeof(BookEntry);
if (!bookFile.good()) if (!bookFile.good())
@@ -402,44 +401,34 @@ void Book::open(const string& fileName) {
} }
/// Book::get_move() gets a book move for a given position. Returns /// Book::probe() gets a book move for a given position. Returns MOVE_NONE
/// MOVE_NONE if no book move is found. If findBestMove is true then /// if no book move is found. If findBest is true then returns always the
/// return always the highest rated book move. /// highest rated move otherwise chooses randomly based on the move score.
Move Book::get_move(const Position& pos, bool findBestMove) { Move Book::probe(const Position& pos, bool findBest) {
if (!bookSize || !bookFile.is_open()) if (!bookSize || !bookFile.is_open())
return MOVE_NONE; return MOVE_NONE;
BookEntry entry; BookEntry entry;
int bookMove = MOVE_NONE; unsigned scoresSum = 0, bestScore = 0, bookMove = 0;
unsigned score, scoresSum = 0, bestScore = 0;
uint64_t key = book_key(pos); uint64_t key = book_key(pos);
int idx = first_entry(key) - 1;
// Choose a book move among the possible moves for the given position // Choose a book move among the possible moves for the given position
for (int idx = first_entry(key); idx < bookSize; idx++) while (++idx < bookSize && (entry = read_entry(idx), entry.key == key))
{ {
entry = read_entry(idx); scoresSum += entry.count;
if (entry.key != key) // Choose book move according to its score. If a move has a very
break; // high score it has higher probability to be choosen than a move
// with lower score. Note that first entry is always chosen.
score = entry.count; if ( RKiss.rand<unsigned>() % scoresSum < entry.count
|| (findBest && entry.count > bestScore))
if (!findBestMove)
{
// Choose book move according to its score. If a move has a very
// high score it has higher probability to be choosen than a move
// with lower score. Note that first entry is always chosen.
scoresSum += score;
if (RKiss.rand<unsigned>() % scoresSum < score)
bookMove = entry.move;
}
else if (score > bestScore)
{
bestScore = score;
bookMove = entry.move; bookMove = entry.move;
}
if (entry.count > bestScore)
bestScore = entry.count;
} }
if (!bookMove) if (!bookMove)
@@ -458,12 +447,12 @@ Move Book::get_move(const Position& pos, bool findBestMove) {
int promotion = (bookMove >> 12) & 7; int promotion = (bookMove >> 12) & 7;
if (promotion) if (promotion)
bookMove = int(make_promotion_move(move_from(Move(bookMove)), bookMove = make_promotion_move(move_from(Move(bookMove)),
move_to(Move(bookMove)), move_to(Move(bookMove)),
PieceType(promotion + 1))); PieceType(promotion + 1));
// Verify the book move is legal // Verify the book move is legal
for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml) for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
if ((ml.move() & ~(3 << 14)) == bookMove) // Mask out special flags if (unsigned(ml.move() & ~(3 << 14)) == bookMove) // Mask out special flags
return ml.move(); return ml.move();
return MOVE_NONE; return MOVE_NONE;

2
src/book.h
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@@ -44,7 +44,7 @@ public:
~Book(); ~Book();
void open(const std::string& fileName); void open(const std::string& fileName);
void close(); void close();
Move get_move(const Position& pos, bool findBestMove); Move probe(const Position& pos, bool findBestMove);
const std::string name() const { return bookName; } const std::string name() const { return bookName; }
private: private:

2
src/search.cpp
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@@ -391,7 +391,7 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) {
if (Options["Book File"].value<string>() != book.name()) if (Options["Book File"].value<string>() != book.name())
book.open(Options["Book File"].value<string>()); book.open(Options["Book File"].value<string>());
Move bookMove = book.get_move(pos, Options["Best Book Move"].value<bool>()); Move bookMove = book.probe(pos, Options["Best Book Move"].value<bool>());
if (bookMove != MOVE_NONE) if (bookMove != MOVE_NONE)
{ {
if (Limits.ponder) if (Limits.ponder)