Arimaa Forum - Print Page


    
      
        Arimaa Forum
        (http://arimaa.com/arimaa/forum/cgi/YaBB.cgi)
      

        Arimaa >> Off Topic Discussion >> Houdini - new chess engine on the rise
        
(Message started by: omar on Feb 11^th, 2011, 9:09am)

Title: Houdini - new chess engine on the rise
Post by omar on Feb 11^th, 2011, 9:09am

Rybka 4 which has dominated computer chess for several years now was defeated in 40 game match by Houdini 1.5, a relatively new chess engine.

http://www.chessvibes.com/reports/free-houdini-beats-commercial-rybka-23-5-16-5/

http://www.thechessmind.net/blog/2011/2/8/houdini-15a-defeats-rybka-4-235-165.html

Title: Re: Houdini - new chess engine on the rise
Post by The_Jeh on Feb 11^th, 2011, 9:20am

I downloaded it and tried it out. It is clearly the stronger engine on my hardware. I did notice that it seemed to have a knack for turning even positions into wins.

Title: Re: Houdini - new chess engine on the rise
Post by omar on Feb 11^th, 2011, 11:53am

Did you have it play against Rybka 4?

I had it play against a version of Rybka 2 that came with Arena and it was certainly much better. Also I noticed the number of positions Hudini was examining was about 10x more than Rybka and it was getting deeper into the tree.

I'm guessing that Hudini's evaluation function is much simpler and it is relying more on searching deeper than on a complex eval function. For a while more complex evaluation functions were prevailing. Maybe Hudini will cause the trend to shift back to simpler eval functions.

Title: Re: Houdini - new chess engine on the rise
Post by The_Jeh on Feb 11^th, 2011, 1:16pm

on 02/11/11 at 11:53:23, omar wrote:

Yes, Rybka 4.

I don't know whether Houdini's eval is simpler. Actually, I think it might be fairly sophisticated, as it seems to evaluate some positions much more accurately than one would expect from a computer. The number of nodes that Rybka indicates it examines is much lower than most other engines. For example, Fruit indicates a much greater number of searched positions than Rybka. At the same time, I agree that Houdini is very fast. At lightning speeds it simply dominates. I did notice that (at certain time controls) its selective search went quite deep - sometimes into the 50-60 ply range. Perhaps it is pruning extremely aggressively.

Title: Re: Houdini - new chess engine on the rise
Post by Janzert on Feb 11^th, 2011, 4:46pm

Remember Rybka rather infamously lies about its node count.

From a recent thread on openchess (http://www.open-chess.org/viewtopic.php?f=5&t=1004)

Quote:

As I've pointed out elsewhere, the "modern" Rybka node-counting method simply counts White make-moves and divides by 7, so it is low by a factor of ~14, or maybe 15-16 if you include null moves in your accounting.

I also seem to recall but can't find a reference off hand that at least older versions also under reported the search depth.

Janzert

Title: Re: Houdini - new chess engine on the rise
Post by qswanger on Feb 11^th, 2011, 5:20pm

Man, the first game of this match where Houdini plays the black side of a Sicilian, goes down/sacrifices three pawns with the queens off the board and no mating attack and ends up winning was just super sweet. Now he *did* have crazy active pieces in the subsequent open position (2B+N vs B+2N) and no pesky pawns were hemming in his rooks and it was amazing to see this agent turn these positional factors into the eventual win of a piece and then grind out a win in the endgame pawn push. Riveting!

Title: Re: Houdini - new chess engine on the rise
Post by Fritzlein on Feb 11^th, 2011, 7:27pm

That was a great game. Computers are not supposed to be able to make positional pawn sacrifices like that.

Title: Re: Houdini - new chess engine on the rise
Post by chessandgo on Feb 12^th, 2011, 4:19am

I can't believe how alien chess games have become to me. It's like someone is talking to me in Chinese. I can see the pieces move, but that's about it :)

Title: Re: Houdini - new chess engine on the rise
Post by rbarreira on Feb 12^th, 2011, 7:51am

on 02/12/11 at 04:19:09, chessandgo wrote:

I can't believe how alien chess games have become to me. It's like someone is talking to me in Chinese. I can see the pieces move, but that's about it :)

Yeah... most of those moves look pointless to me.

Title: Re: Houdini - new chess engine on the rise
Post by omar on Feb 13^th, 2011, 9:04am

When the moves are made by looking at the consequences 10 plys or more later, the spectators need to be able to also look that deep to really appreciate the significance of the move. I think this is what make chess difficult for average people to follow without the help of a grandmaster explaining the reasoning behind the move. But now even the grandmasters are needing to use computers to understand the moves. Problem is the computer is not good at explaining it :-) I guess from a high level one can still appreciate games that swing back and forth and have some drama even if one can't appreciate the details of each move.

Title: Re: Houdini - new chess engine on the rise
Post by Fritzlein on Feb 13^th, 2011, 1:29pm

on 02/13/11 at 09:04:03, omar wrote:

Problem is the computer is not good at explaining it :-) I guess from a high level one can still appreciate games that swing back and forth and have some drama even if one can't appreciate the details of each move.

Yes, I can appreciate some drama and unexpected moves, but part of the problem is that it is hard for me to even know if there has been a swing. Was black winning the whole way, or was there a dramatic blunder by white? If so, when? My level of enjoyment of chess as a spectator is limited by my poor chess ability. Grandmaster commentary would definitely help, but then I would still be limited by how well I understand what the grandmaster is saying. Ultimately the best fans of a game are the best players.

Title: Re: Houdini - new chess engine on the rise
Post by The_Jeh on Apr 19^th, 2011, 9:36am

Houdini and Rybka have again made it to the Elite Match in TCEC Season 2. Houdini is the same version, 1.5a, but Rybka has been upgraded to version 4.1, which fixed a bug that affected time management. So far, the match is tied with about a fourth of the match left to play.

Title: Re: Houdini - new chess engine on the rise
Post by omar on Apr 20^th, 2011, 4:24pm

Thanks for the update. Here is the link:

http://www.tcec-chess.org/tcec_em.php

Title: Re: Houdini - new chess engine on the rise
Post by Fritzlein on Apr 20^th, 2011, 11:27pm

John, thanks for tipping me off about the rematch. I watched a few of the games live (while doing other things, of course, since the time control is slow and there is no GM commentary). Houdini now has a three point lead with three games to go, so Houdini is repeat champion barring a miracle run by Rybka.

Watching the games is spooky, in that they alternate between moves that have some obvious purpose even I can understand and moves that are so obscure I would call them blunders if I didn't know I was watching some of the best chess that has ever been played by anyone!