Computer Chess Club Archives




Subject: Re: Secrets of Rybka and Fruit from my point of view

Author: Uri Blass

Date: 16:18:37 12/15/05

Go up one level in this thread

On December 15, 2005 at 17:44:24, Jaime Benito de Valle Ruiz wrote:

>On December 15, 2005 at 17:05:00, Sergei S. Markoff wrote:
>>1) Fruit.
>>Fruit search seems to be primitive. "History pruning" is a variation of
>>well-known idea. After implementing such method in SmarThink some years ago I
>>named it "history-based pruning" and then changed to "ordering-based pruning".
>>The outcome of such methods very depends of whole search model, but anyway
>>history pruning is not the key to Fruit strength.
>>To my mind, the key of Fruit strength is that the "Chess is the art of
>>exchange". So, Fabien's idea about flexible game stages looks to be a beautiful
>>way to improve positional play. Fruit can effectively consolidate the position.
>>It simply knows when to excange to improve position. I think that it's the main
>>key (cumulative with very good tuning of evaluation function). I think Fruit is
>>very perspective. The main line of progress for this project, to my mind, is to
>>add more complicated knowledge and intellectualize a search.
>I completely agree with you. People overestimate FruitĀ“s search, and
>underestimate its eval because it looks simple.

I also agree and I never underestimated fruit's evaluation.
It is possible that the main reason for it's superior evaluation is the idea of
average between opening and endgame but it is fact that it has a superior

I have also theory that superior evaluation helps more at long time control.
I try to prove or contradict this theory by matches against tscp when tscp
searches deeper than Movei and I will be happy if other programmers repeat the

The idea is to give movei the same search algorithm as tscp(simple qsearch and
extending checks by 1 ply but only when the remaining depth is at least 1).

I play the Noomen match between Movei and tscp

Results so far:
Tscp 2 plies-Movei 1 plies 72-28
Tscp 3 plies-Movei 2 plies 75-25
Tscp 4 plies-Movei 3 plies 56.5-43.5
Tscp 5 plies-Movei 4 plies 18-18



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