Hi everyone. I’m attempting to increase the opening tree of Deep Rybka 4 & when I try to move the database it comes with over to the tree it asks in a little box under length if I want absolute strength or ECO-relative strength. Does anyone know what that means? Thanks in advance.
nope.
nope.
I’m sure someone at the Rybka forum could answer that question. I would imagine using “absolute strength” would create a smaller opening database, using only the strongest lines. Dunno the cutoff, but probably around 2500+ ELO
Using “eco strength”, would entail it to include all games, probably games 2100+ ELO, although some programs might keep lines into the 1800+ elo range.
Using only lines from GM games gives you better play, but misses out a lot of theoretical lines that might be played by lower level players, or lines that are “interesting”, but not well researched.
Thank you, I appreciate the thought.
My guess would be that ECO refers to Encyclopedia of Chess Openings, not the ratings. I don’t know what ECO-relative strength means though.
Someone posted a similar question on the Rybka forum, but only got comments from the peanut gallery.
Since no one has the answer, I’ll give you my guess. Using my programmer’s intuition, if I had put a question like that in the UI, it would have meant something like this:
A player’s absolute strength would be based on an external source, or on the total of all the games that he/she played in the database.
A player’s ECO relative strength would be modified for each ECO code to reflect his/her performance in the subset of the games that he/she played in that opening. This might make a difference if, for example, a particular player always seemed to lose when playing the Sicilian Dragon, but was a much stronger player overall.
Jim
Perhaps a typo and the choices are meant to read ‘Absolute length’ and ‘ECO-relative length’, not ‘strength’?
Following is the Help from ChessBase 11 for Absolute length vs. ECO-relative length when used in similar functions.
Regards,
John
Length
Crucial for the size of the resulting tree is the length of the variations which are put into the tree. It is not very meaningful to put entire games into it, so you should truncate them at a specific point.
ChessBase allows you to limit the length of the variations in two different ways.
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You can specify that the absolute length of every variation should be exactly “n” moves.
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It is usually much more sensible to limit the length of the variations relative to the ECO classification. This results in long variations for theoretical main lines (ECO classification position found late in the game) and short variations for side lines i.e. early deviations.
Obviously, if you choose a shorter length the tree will be compact. But then you are liable to lose some valuable information. If you choose a very large value then the tree will be gigantic, and it will contain a lot of superfluous information. A good practical value for adding games to the tree is the default of ECO + 20.
This comes from Chessbase as it applies to Fritz…possibly the same for Rybka…I personally use a value of 30-ECO relative length and am still experimenting…
Absolute length means that each variation will be cut off at the same point; the default value of “20” means that every variation in the tree will be ten moves long (20 Ply).
If you select ECO relative length, main line variations will likely be longer than whatever you set as the default length, while seldom-played sidelines will often be shorter than your chosen default length.
Using an Alekhine Defense database (as an example) and selecting “ECO relative” with a default length of “20” gave some main line variations that were nearly sixty plies long (three times the default value “20” selected) because they contained frequently-played “known” theory.