Author: Serge Desmarais
Date: 14:58:58 09/09/98
Go up one level in this thread
On September 09, 1998 at 09:34:07, Amir Ban wrote: >On September 08, 1998 at 23:36:05, Serge Desmarais wrote: > >>On September 08, 1998 at 19:16:58, Robert Henry Durrett wrote: >> >>>On September 08, 1998 at 12:24:07, Don Dailey wrote: >>> >>><snip> >>> >>>>I think it is still fundamentally superior to the other programs. It >>>>may not actually be the very strongest currently, but this may be because >>>>Richard has not made any substantial effort to stay ahead and I also >>>>don't think the book is engineered as well as the top contenders, which >>>>could be a big part of the reason his program is not dominant right >>>>at the moment. >>>> >>>>- Don >>> >>>Your observation that you don't think "the book is engineered as well as the top >>>contenders" sounds like an interesting concept. I get the impression that >>>playing Genius with the Fritz book would not completely null out the Fritz >>>advantage because, I assume, the Fritz book is "engineered" for Fritz. I >>>presume that this means that the Fritz book lines are selected to optimize Fritz >>>performance by covering up specific weaknesses of Fritz and capitalizing on >>>specific strengths of Fritz. If this were so, then forcing Genius to use the >>>Fritz book would not be optimum for Genius because Genius's specific weaknesses >>>and strengths might be different from those of Fritz. >>> >>>If the above is an accurate portraial of what you meant by the book being >>>"engineered," then forcing Fritz to play with the Genius book would be equally >>>non-ideal. >>> >>>I wonder if a match between Genius and Fritz, with Fritz being forced to use the >>>Genius book would result in more equality in the win/loss/draw results of such a >>>match. In other words, if the problem were primarily one of book engineering, >>>such a match would point this out. >>> >>>Am I anywhere near close to what you were thinking? >> >> >>Here is how are made the Fritz books : you take a database of HUMAN games of >>relatively high quality (as they say/suggest in the Fritz book) --which means >>the players have a high rating and the time controls were 40/2 or the like-- and >>you import these games into the/an opening tree. Of course you do not import ALL >>the moves of each games, but EITHER a certain FIXED number of half-moves ofor >>all the games (between 1 and 99) OR ECO-like lenght PLUS a certain number of >>half-moves for all the games (between 0 and 99). >> >>Now, BESIDES the moves played by humans, Fritz also import the game scores, >>number of games, average elo rating of the players and links these to every >>respective moves. For example, you import 100,000 games into the tree ; in >>60,000 of these, the first move played was 1.e4 ; 1.d4 was played 30,000 times >>and so on (these number are fictitious). Let's go back to the 1.e4 move (played >>60% of the time. The average rating of the players who chose that first move was >>2540 and their rating performance with that move was 2580. Of all the 60,000 >>games 25,000 were wins, 15,000 were draws and 20,000 were losses. >> >>Now here is HOW Fritz picks its moves : at base, it takes the popularity of the >>move (% of times played) and then balance it with the % of wins (score), ratings >>of the players and performance rating of the moves (don't ask me the >>mathematical formula!) to decide a percentage of chance of playing it in a game. >>Later, it will refine this percentage by adding a value based on its "learned >>experience" when playing that move (you can also manually change the scores). >>But you have to know that Fritz will NEVER play a move that was played only ONCE >>if there are much more popular choices. It will NEVER play a move that has lost >>100% of the time or has a sensible negative score (UNLESS it is the ONLY move in >>book for that position, and even in that case it would have avoided the line >>earlier). In the Fritz basic book, there are NO preset values (manually >>adjusted) for any move. It contains over a million moves/positions with all the >>known main lines for every major opening. >> >> >>Conclusion : Except for a careful chosing of the games imported in the basic >>book, there is NO manual fine tuning of Fritz book by the programmer! But the >>program will/should do it automatically. Winning more often with the moves that >>best fit its "style", the learning will be very positive, thus ending in more >>and more chances of playing these moves, if not EXCLUSIVELY these moves! >> >> >>I think Crafty uses a similar process and I think I remember Robert Hyatt saying >> that Chessbase kind of "copied" Crafty's book learning for Fritz. >> >>Serge Desmarais > > >What you describe here sounds pretty accurate, but is not what is called "book >learning". "Book engineering" sounds more accurate to me. Perhaps the Fritz book >learning came from Crafty, but not this. > >To my knowledge, no one has been as methodical in the automatic generation of >books, or put it on such a sound logical basis (as you describe) as ChessBase. >They should be allowed the credit for that. > >Amir I was not criticizing Chessbase. I think their book concept is very good, finding all the possible transpositions. It is also good for me to learn about ideas in the opening stage, improving what I did play in the past in specific positions (and the scoring stats are very interesting too). Serge Desmarais
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.