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Houdini Lags?

Posted: Thu Oct 06, 2011 4:17 am
by kingliveson
According to Uly here,
Uly wrote: If Houdini is the topic of discussion, I'd find more interesting to discuss why is it lagging behind Rybka and other engines like Critter for analysis of Correspondence games despite the new learning feature that was introduced and that its elo is much higher for unassisted games? Is it the evaluation or what?
What is the evidence behind this -- are you saying with extended time, Houdini plays worse? I dont have the new Houdini so I dont know about the newly introduced features.

Re: Houdini Lags?

Posted: Thu Oct 06, 2011 4:41 am
by Uly
kingliveson wrote:are you saying with extended time, Houdini plays worse?
No, I'm saying that for interactive analysis of correspondence games, when relying on Houdini, it produces worse moves, ideas, or/and evaluation scores of positions than Rybka 4, Critter, Stockfish, and even engines of lower elo like Komodo or Zappa Mexico II.

As a person that uses many engines for analysis this has been my personal experience.

At some point I found it counter-intuitive, and thought it should have been only me, or that the analysis methods I used were bad for Houdini (i.e. if the engine really has higher elo than the others, it was possible my analysis methods didn't suit Houdini well, and not the other way around).

But then started reading comments of other correspondence chess player on Rybka Forum, depicting the same. SEVERAL players, you mention how bad Houdini is for analysis, several posters jump and agree with you.

I have concluded that this is true after reading Moz's posts, he seems very sensible in his criticisms and also complains about the positions in where Rybka under-performs (so this is not fanboyism). He is a Houdini supporter and suggests people to buy the engine because the new features are very useful. Yet, he claims that for analysis, Houdini 2 is still worse than Rybka 4, depicting the same problems that Houdini 1.5a had.

I don't have H2, but I believe him.

So far we only have anecdotal evidence and no easy way to show more (because Correspondence games last months! by the time we have data showing strong evidence of it, it's no longer relevant and Houdini 4 is already here...), but the question is more like, what is causing this phenomenon? (the phenomenon is real. For instance, assume that Houdini is really the best for correspondence chess games, then, what would lead people to believe that it isn't and to fail to use it properly to find the best move? That's also something interesting even if Houdini isn't worse).

A striking difference between normal games and interactive games is that in the former, a move is made and it's done, while in the latter, you can make the move, see the resulting positions, and take it back, and look if there's something better. That's the core of analysis and with Houdini, if it doesn't understand a variation then it's going to suggest more and more moves that also don't work, while other engines tend to have a mainline, and when the mainline is wrong, it's easier to kill it and make the engine understand the variations are bad and make it agree with the moves of an engine that understands the position better, while Houdini is stuck in stupid.

I really believed that the learning feature was going to help in this, surely if you show Houdini how wrong it is on some variation and it learns about it, it's expected that it goes back to better mainlines and provides useful analysis? But Moz reports that, nope, learning isn't helping, Houdini has a core issue that doesn't let it perform like one would expect from an engine of its elo.

Re: Houdini Lags?

Posted: Fri Oct 07, 2011 2:46 am
by tano-urayoan
As I said before this are just opinions are everyone has one.
First there are just a few serious* CC players that plays in Rybka forum.

Second as the name of the forum suggests must expressed a biased opinion a)in favor of Rybka b) against Houdini. Could they present serious evidence about their opinions, maybe there are positions where Houdini has a bad evaluation, or silly plans but that could be said about all chess engines, there are no perfect engine yet (or maybe there exists but is private). So how you demonstrate that Rybka is superior to Houdini for Correspondence analysis.

An option is create a correspondence testsuite (based in correspondence games) and test the engines there.

Other option is to make a survey across different correspondence organizations to inquiry their members about their favorite engine, but again it will be a personal opinion.

So why all the resentment against Houdini over there?

* I define serious CC players as the ones that take part in official organizations mainly the ICCF.

Re: Houdini Lags?

Posted: Fri Oct 07, 2011 9:11 am
by Hood
If Houdini is worse for CC games is disputable. The learning feature is not working properly but... it finds the moves which Rybka does not find.
Other phenomenon I noticed is that Rybka 4 might perform better then Rybka 4.1 ?!

Rgds Hood