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- - By Vasik Rajlich (Silver) [pl] Date 2010-05-26 18:20 Edited 2010-06-18 08:06
Rybka 4
May 26, 2010

Overview

Rybka 4 is the latest UCI Rybka chess engine. The changes since Rybka 3 are extensive.

General Changes

- The evaluation is more accurate and better aware of king safety and other dynamic factors.
- The search is more efficient in every major category of position.
- Some new endgame heuristics have been added.
- The overall engine behavior has been cleaned up and made less quirky.

New Features

- New parameters controlling engine output, engine priorities, and engine time management during game play.
- Ability to take advantage of large memory pages (_link_) and SSE4.2 and SSE4a instruction sets.
- New logging capability, which documents in .html the evolution of the main line for all analyzed positions.
- Asymmetrical piece scoring (see below).

Asymmetrical piece scoring

It is now possible to adjust all piece values for both colors in Rybka 4. This functionality has three uses:

1) Rybka can be informed that some pieces in some specific position should or should not be traded.
2) Setting higher overall piece values for one color implements contempt. Rybka will attempt to not trade the more valuable pieces, keeping more tension in the position, and she will give higher evaluation scores to the side with the more valuable pieces and therefore avoid draws by repetition.
3) Piece values which are more consistent with top GM practice can be used. For still-unknown reasons, rooks and queens tend to be more valuable in computer play than what top human players believe to be correct. The default values are optimized for computer play. GM Larry Kaufman recommends the following adjustments as more human-like: pawns=0, knights=24, bishops=24, rooks=12, queens=0. (_link_)

Please note that contempt is now off by default and should be set manually when appropriate.

More information

Please see the Rybka 4 user area (_link_) or visit our forum (_link_) for more information.

Credits

A huge thanks to everyone on the Rybka team, as well as to everyone else who has contributed in any way.

- Lukas Cimiotti, for systematically pushing our clustering project through all sorts of ups and downs to being the weapon and asset which it is today, and for the comically shocking effect produced by his mountain of hardware.
- Jiri Dufek, for an awesome Rybka 4 book, for his pragmatic and highly successful tournament preparation, and also for some useful networking skills.
- Jeroen Noomen, for the groundbreaking Rybka 3 books, for several years of superb tournament preparation, and for making sure that Hans stays out of trouble.
- Nick Carlin, for his unique scientific brand of book preparation, for delivering several tournament victories in a short but productive period of time, and for returning to make sure that Rybka 4 was done right.
- Felix Kling and Christoph Kling for our excellent web site, for interesting reports, and for keeping the forum free from marauding bandits.
- Larry Kaufman, for his innovative man vs machine matches, for countless suggestions about quantitative aspects of Rybka's evaluation, and for helping with the release and tuning the human material weights.
- Hans van der Zijden, for going anywhere and everywhere to operate and represent Rybka, for proudly wearing whatever "medals" tournament organizers foist on him, and for staying out of trouble.
- Dadi Jonsson, for hosting the Rybka forum - the best forum I have seen on the internet - and giving Felix something to keep free from marauding bandits.
- Steinar H. Gunderson for Microwine, which allows Rybka to run on Linux despite my chaotic coding practices, allowing Felix to remain in the dark about the modern invention that is Windows.
- The Rybka 4 Beta testers for a fun, lively and productive Beta testing period: Majd Ansari, Wieland Belka, Shaun Brewer, Nick Carlin, Lukas Cimiotti, Jiri Dufek, Mathias Feist, Steinar H. Gunderson, Dadi Jonsson, Larry Kaufman, Felix Kling, Joachim Nettelbeck, Jeroen Noomen, Kostas Oreopoulos, Ulysses P., Teemu Pudas, Albert Silver, Shahar Tzafrir, Ernst Walet and Victor Zakharov.
- Mathias Feist, Matthias Wuellenweber and Frederic Friedel from ChessBase, for their organized, professional work, for showing me how a small business should be run, and for putting up with my learning curve on release issues.
- Victor Zakharov, Sergey Abramov and their team from Convekta, for their great enthusiasm, energy and creativity, and for having no fear of the impossible
- Nelson Hernandez, for a professional-quality video interview, complete with interesting background noises, and for provoking me into all sorts of predictions and statements which have so far not come even remotely close to being realized.
- Alan Sassler, for walking me through the arcane issues involved in tuning highly correlated feature sets.
- Shahar Tzafrir, for making sure that our cluster has a tough opponent.
- Rybka forum regulars, for all kinds of ideas, and for making sure I keep my feet on the ground.
- For anyone I may have accidentally left out.
- And, saving the best for last, to Iweta, for being great!

What's Next?

I'll keep the details a surprise, but we'll have a very cool announcement within two weeks.
Parent - - By Vasik Rajlich (Silver) [pl] Date 2010-05-26 18:21
BTW, Felix: this isn't a final version yet, I'll need to proofread and probably add a few things. I'll let you know when we have a website-ready version.

Vas
Parent - By Felix Kling (Gold) [de] Date 2010-05-26 21:00
as always - take your time :)
Parent - - By Felix Kling (Gold) [de] Date 2010-05-26 21:03
You forgot to mention Steinar. It's a shame. :)
Parent - - By Vasik Rajlich (Silver) [pl] Date 2010-05-27 02:13
Ouch - fixed - and sorry. Thanks Steinar!

Vas
Parent - - By Felix Kling (Gold) [de] Date 2010-06-17 20:14
He was also a beta tester :)
Parent - By Vasik Rajlich (Silver) [pl] Date 2010-06-18 08:06
Fixed. Anything else that Steinar did that I forgot about? :smile:

Vas
Parent - By irulats (****) [ie] Date 2010-05-26 18:23

>and also for some useful networking skills


:)
Parent - - By yanquis1972 (****) [us] Date 2010-05-26 18:33
I'll keep the details a surprise, but we'll have a very cool announcement within two weeks.

hmm, can you at least let us know whether or not it costs us money? :D
Parent - - By Ernst (***) [nl] Date 2010-05-26 18:59

> hmm, can you at least let us know whether or not it costs us money? :D


Not at all, the announcement will be complete free. :-D
Parent - By notyetagm (**) [us] Date 2010-05-26 20:54
LOL

:-)
Parent - By Felix Kling (Gold) [de] Date 2010-05-26 21:01
the announcement will be like "it's a boy"/"it's a girl" :)
Parent - By Vasik Rajlich (Silver) [pl] Date 2010-05-27 02:14
Just wait and see! :)

Vas
Parent - By jackwelb (*) [us] Date 2010-05-29 04:11
My guess for the "very cool announcement" --> Vas will supply the chess engine for the next edition of the Chessmaster series.  That would be very cool!!
Parent - By Dragon Mist (****) [hr] Date 2010-05-26 19:01
God I missed all this fun! Just as good old times (_link_).
Parent - - By Uly (Gold) [mx] Date 2010-05-26 19:18

> Please note that contempt is now off by default and should be set manually when appropriate.


How can contempt be set? (unless you mean "Asymmetrical piece scoring = Contempt", which is unclear).
Parent - - By Christian Packi (****) [de] Date 2010-05-26 23:47
I think he means if you set all your pieces to e.g. 0.1 R4 will avoid exchanging those for the opponents pieces which are less valueable.
Parent - - By Vasik Rajlich (Silver) [pl] Date 2010-05-27 02:15
Yes, exactly. I'll document everything this weekend.

Vas
Parent - - By Akbarfan (***) Date 2010-06-07 23:05
Did I miss something?
Parent - By Vasik Rajlich (Silver) [pl] Date 2010-06-08 20:56
I'm behind schedule, this is still on the list of course.

Vas
Parent - - By Olympus (*) [us] Date 2010-05-29 12:53
I tried this, changed all pieces, except pawns, to 0.1. Next time i opened the configuration window, the values had been changed to -1000. Is this normal or not?
Parent - - By Vempele (Silver) [fi] Date 2010-05-29 12:55
Which GUI? And do you mean you literally typed "0.1" and not 10 (centipawns)?
Parent - - By Olympus (*) [us] Date 2010-05-29 13:40 Edited 2010-05-29 13:44
The Arena GUI. And yes, i typed "0.1".

Edit: Did further testing, anytime i enter a value with a decimal point, for example 1.1, they are changed to -1000.
Parent - - By Vempele (Silver) [fi] Date 2010-05-29 13:44
The value has to be an integer. Besides, I don't think Rybka even evaluates in millipawns.
Parent - By Olympus (*) [us] Date 2010-05-29 13:47
Thanks. I was just following the tip by Christian in his post above. :-)
Parent - - By cma6 (****) Date 2010-05-27 00:21
Vas: how would one implement this: The default values are optimized for computer play. GM Larry Kaufman recommends the following adjustments as more human-like: pawns=0, knights=24, bishops=24, rooks=12, queens=0. (_link_)?
       It does not make sense to have the Q have 0 value, unless those values abovve are changes to certain values. If so, how does one change the unknown values and to what new values?
Parent - - By Uly (Gold) [mx] Date 2010-05-27 00:48

> It does not make sense to have the Q have 0 value


It means "0 offset from defaults", that's why you can set negative values.

> If so, how does one change the unknown values and to what new values?


You look at the engine's score of a given position and tweak them until Rybka scores them as you want. Larry looked at 20 materially unbalanced theoretical positions to get his values (he didn't need to know the actual piece values, just how pieces appeared relative to each other on Rybka's evaluation scores.)
Parent - - By cma6 (****) Date 2010-05-27 00:59
Thanks, Vytron, that makes sense. But let's say we just want to make the changes that LK suggests to achieve a more "human", i.e., B & N +24 etc, so that we have have a more "human" R4 since we are playing very strong centaurs in correspondence chess. How would we make those changes semi-permanently in R4?
Parent - - By Leto (***) [us] Date 2010-05-27 01:10
I think once you make the edits in the parameter settings the changes will remain until you change them again.
Parent - By Vasik Rajlich (Silver) [pl] Date 2010-05-27 02:15
Yes, exactly.

Vas
Parent - - By Uly (Gold) [mx] Date 2010-05-27 05:49
You need to create a personality file on your GUI (e.g. a personality called "R4 Human"), so you load this personality or the default personality when you need it.
Parent - - By Olympus (*) [us] Date 2010-05-27 13:06
What should be the extension of this personality file? .per, .txt, or something else? And can you show us a sample of how this file should be formatted?

In the Arena configuration window for Rybka 4, i don't see any way to load a personality file. How exactly to load a personality file?
Parent - - By Uly (Gold) [mx] Date 2010-05-27 17:58
This is a GUI issue, for personalities the GUI should allow you to save the engine settings as if they were a different engine.
Parent - - By Olympus (*) [us] Date 2010-05-27 19:10
In Arena, you can change the settings, then click the "Save as New Engine" button. This does the same thing as duplicating an engine and changing the settings. But a "personality file" is not created or saved!!

I suppose something must be saved to the registry, so Arena 'remembers' these settings.
Parent - - By Uly (Gold) [mx] Date 2010-05-27 19:17

> In Arena, you can change the settings, then click the "Save as New Engine" button. This does the same thing as duplicating an engine and changing the settings.


That's what I meant by "personality".
Parent - - By Olympus (*) [us] Date 2010-05-27 19:28
Ok, but you said "personality file".
Parent - By Uly (Gold) [mx] Date 2010-05-27 20:03
Yeah, maybe that was my mistake. Arena creates a file from where she reads the parameters of the new engine you created, that's what I call the personality file.
Parent - - By cma6 (****) Date 2010-05-27 13:21
What is a personality file?
Parent - By Uly (Gold) [mx] Date 2010-05-27 17:59
Personality files (note that's how I call them, each GUI has its own name for them) are a way for the GUI to store different engine settings.
Parent - By yanquis1972 (****) [us] Date 2010-05-27 17:58
if you're not using a chessbase GUI you can save the settings as its own engine. i've never figured out how to install a tweaked engine into the chessbase gui (ie i have to change settings every time, or load from a saved file, which is just as much of a pain).
Parent - - By Zadig (**) [gb] Date 2010-05-27 21:10 Edited 2010-05-27 21:12
"A huge thanks to (...) ChessBase (...) for showing me how a small business should be run, and for putting up with my learning curve on release issues"

Vas, please allow me a friendly comment on that, as an admirer of Rybka and as a retired successful small business manager, with all due respect.

I don't think that I am alone in thinking that Chessbase's approach to "release issues" is sad: no customer dialogue or support to speak of, vapid new versions, no updates, etc... To see you going down the route of emulating them is simply disheartening. And let me tell you why is consider it the wrong ethical choice.

Like you, I was fortunate enough to have a gift that put me on top of my (modest) field. Like you, I offered stunning value for the price versus competition. Competitors were calling me, kindly suggesting me to push up my price: "You could sell it for much more. Come on." "You don't have to offer some much for such a price", etc... But at the end of the day, it was between me and my clients, my "fans". Yes I could extract more from them. Moneywise. Well, only some of them: those who would afford the new price point, the new, deteriorated value proposition. So I maintained permanently opened client relationships even when success and fame meant that, honestly, that was not economically justifiable. I have never skimped on the performance offered, only the best allowed by my capabilities at all times, even though the competitive field did not require it. The I-could-do-better-but-my-product-is-good-enough-for-you-to-buy-it-as-is-mr-client approach is just ethically bankrupt. As is a worsened reputation in exchange of more money. It is all about a balance between what you give back to the community thanks to your gift and ... greed. Greed. Your client base senses - correctly I believe - a new, deteriorated value proposition. It senses that greed has gone up several notches. I am saddened that you have apparently taken that decision, under the regrettable influence of Chessbase, but, unlike many, I am not resentful: I respect the freedom of the entrepreneur and his newfangled mercantile cynicism.

I won't buy Rybka 4 though. I can afford it many times over, but you've lost my trust, I'm afraid, exactly like Chessbase did a long time ago with its so-called "releases".
Parent - - By Bobby C (****) Date 2010-05-28 21:14

>The I-could-do-better-but-my-product-is-good-enough-for-you-to-buy-it-as-is-mr-client approach is just ethically bankrupt.


Yeah and in your business I bet you never had half of your product stolen everytime you made a new product. You can not compare the business of computer chess to most business.
Parent - - By Zadig (**) [gb] Date 2010-05-29 16:08
Stolen?

If you refer to Rybka cloning, and unless I've missed a step, its illegality has never been established or even argued in court. So the presumption of innocence applies.
Parent - By rookie (**) [us] Date 2010-06-02 11:10
There is no one to sue, as the cloners are anonymous.
Parent - - By Vasik Rajlich (Silver) [pl] Date 2010-06-04 14:23
Thanks for the comments. Let me just clarify my statement from the release notes. Nobody is meddling in what I am doing. :) I just felt that ChessBase sets a good example in patiently focusing on the few things that matter and not giving undue importance to the things that don't.

I am sure as a former small business owner you realize the value of concentrating your limited energies.

Vas
Parent - - By Zadig (**) [gb] Date 2010-06-04 19:14
I do.

I wish you the best of luck with your new rental business model anyway: it is an exciting experiment, even if it possibly sounds like very bad tidings for the impecunious hobbyist.
Parent - By Vasik Rajlich (Silver) [pl] Date 2010-06-05 11:22
Thanks. :)

We'll have some things for the impecunious hobbyists out there too, but it will take a couple of years.

Vas
- - By Brettangst (**) [de] Date 2010-05-27 19:07
Rybka4 on each hardware will be stronger than Rybka3?
Parent - By Dragon Mist (****) [hr] Date 2010-05-27 19:08
Yes.
- - By cess.book557 [hu] Date 2010-06-09 10:10
Best Cool Pics Rybka 4 , Hun super.
http://baloghcsaba.com/1/rhun .jpg
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