Re: Problem compiling opening book on Gnu Chess 5.4.

[Simon Waters]

"Sternbach, William [IT]" wrote:
> 
> While building the book,
> I got numerous illegal move warning messages
> while building the book like this:
> 
> Illegal move 74. ... {source

> New & unique added: 735848 positions

> 1)  Is this normal.

Hi William,

this certainly was normal, although it should have been much
improved with the following opening book.

ftp://ftp.gnu.org/gnu/chess/book_1.00.pgn.gz

Is this the file you used?

> 2)  Has anyone else had trouble like this building the book?

The current PGN parser has trouble with comments, this will be
fixed in 5.06.
 
> 3)  Is the opening book usable with these errors?

Yes, it may have less positions than if you use a comment free
PGN file, but as long as the book.dat file is found when GNU
Chess starts it will be used.

The command "bk" (or "book" in {X|Win}board) will show if the
current position is in book with a brief summary of how what
moves gave what result.

You can supplement the book with any PGN files, or build your
own preferred book by feeding it games with relevant openings.
The free software chess database tool SCID can be used to
prepare appropriate PGN files, and was very helpful in cleaning
the book up. The supplied opening book is just intended as a
comprehensive selection of games to get users started, whilst
some minimal work has gone into to tuning the book, I don't
think it can be considered as special in any way. 

 Simon