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Brent Baccala
Member since Jul-26-06 · Last seen Sep-13-18
This chessforum is currently dedicated to the development of Hoffman, a endgame tablebase generator.

The two most important predecesors to Hoffman are the Nalimov tablebases and Eiko Bleicher's Freezer. Hoffman combines the capabilities of Nalimov and Freezer.

Nalimov solves the endgame completely, back propagating from one tablebase to another (for example, KQK is needed to evaluate queen captures in KQKQ), but due to the complexity of the analysis it is limited to roughly six pieces in play. Freezer allows pieces (especially pawns) to be restricted to particular squares and is thus able to solve more complex positions with a dozen or more pieces in play, albeit with restrictions (i.e, it can't solve the endgame completely). The biggest problem with Freezer is that it can't back propagate from one tablebase to another the way Nalimov can, thus it's ability to evaluate exchanges and queening combinations is very poor.

Hoffman combines both approaches into one. It is capable of both back propagation and piece restriction. For example, in the rook-and-pawn endgame we were about to enter in The World vs A Nickel, 2006, it could restrict the pawn movements (like Freezer), and thus calculate how White could go about queening a pawn, while still making a meaningful evaluation of rook trades by back propagating (like Nalimov) from a tablebase solution of the king-and-pawn endgame.

Hoffman was originally intended for use in Chessgames Challenge: The World vs A Nickel, 2006, but that game ended with a win for the World Team, as did Chessgames Challenge: Y Shulman vs The World, 2007 and Chessgames Challenge: The World vs G Timmerman, 2007, without any use of Hoffman in those gamea. I resigned from the World Team after they accepted a draw in Chessgames Challenge: A Nickel vs The World, 2008

The program can be downloaded from http://www.freesoft.org/software/ho..., part of my website, www.freesoft.org

>> Click here to see Brent Baccala's game collections.

   Brent Baccala has kibitzed 277 times to chessgames   [more...]
   Aug-02-16 V Stepovoj vs E Chasovnikova, 1996 (replies)
 
Brent Baccala: Reminds me of a kibitz on FICS. Lecturebot: Would you like to see this in one of your games? Me: only if I'm white
 
   Jul-09-10 G Rajna vs P Lukacs, 1977 (replies)
 
Brent Baccala: Not sure what alternatives black had to 33 ... Rc7, but it was clearly a tactical blunder that walks into the puzzle position 34. ?
 
   Nov-20-09 H P Garcia vs R A Ziatdinov, 1994 (replies)
 
Brent Baccala: I just noted that after Re4, Rxe4, white can recover the rook. After the knight fork, black's king has to move to either g7/g8, where Qg3 forks the rook on h4, or to e8, where Qxc6 forks the rook on a8.
 
   Feb-24-09 A Nickel vs The World, 2008 (replies)
 
Brent Baccala: All right. I came home, hit refresh... and breathed a big sigh of relief. It would have been a lot more work for me if the team had voted to continue. My resignation from the World Team is now final, but this doesn't have very much to do with what has happened over the last ...
 
   Jan-29-09 kutztown46 chessforum (replies)
 
...
 
   Jan-22-09 M Umansky vs The World, 2009 (replies)
 
Brent Baccala: <kwid>, I am a patzer. I am a 39 year old American who works mostly with technology - physics, math, computers. I have played in two chess tournaments in my life, once in college and again a few years ago, and both times concluded that I wasn't adequately prepared and ...
 
   Nov-26-08 Open Defence chessforum (replies)
 
Brent Baccala: Our thoughts and prayers are with you this Thanksgiving night.
 
   May-26-08 The World vs G Timmerman, 2007 (replies)
 
Brent Baccala: FYI - I've released version 1.0 of Hoffman (the tablebase generator) at http://www.freesoft.org/software/ho... If you hated the XML before, well, no need to bother with the download because there's still no GUI. But I've tried to get it to release quality and put it out ...
 
   Jan-23-07 Brent Baccala chessforum (replies)
 
Brent Baccala: <ganstaman: Maybe after 1...Rxa6 2. Rxa6 Qxb7 things are simplified enough for computers, but I'm unsure as to how to continue> That's basically a five piece problem at that point. Hoffman can't quite do that yet, but maybe in month or two we could revisit this.
 
   Jan-12-07 Y Shulman vs The World, 2007 (replies)
 
Brent Baccala: Well, like I said, I hardly ever voted in the Nickel game, but with the closed voting system, I better change that policy for this game. For now, I'm going with the numbers: Repertoire Explorer: Yury Shulman (white) 1. ... Nf6
 
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