Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: What are the different metrics for egtb

Author: GuyHaworth

Date: 15:19:40 12/15/05

Go up one level in this thread



DTC = Depth to Conversion, i.e. to change of force and/or mate

DTM = Depth to Mate

DTZ = Depth to (move-count) Zeroing (move),
      i.e. to Pawn-push, change of force and/or mate

DTZk = DTZ given that a k-move draw-claim rule will be used to claim a draw
      DTZk =< DTZ and as 'k' increases, DTZk does not increase

Metrics DTCk and DTMk may similarly be defined ....


and more subtly:

DTR = Depth (by) The Rule, i.e. the k-move (draw-claim) rule
      i.e. the least k for which a win is possible under a k-move rule

DTZR = Depth to (move-count) Zeroing (move) while minimaxing DTR
       DTZR =< DTR

DTZR clicks down as a DTR-minimaxing line progresses, and is needed to see what
the optimal moves are, as DTR often does not change for several moves, e.g. in a
KBBKNN endgame.

There are no DTR or DTZR EGTs yet, except in a theoretical, Platonic sense

One would not see needless sacrifices by the winner, or the loser refusing to
take a piece in a DTR-line.  But the main point is that if a position is
winnable under a k-move rule (whatever 'k'), the DTR-line will win it.


Move-filtering strategies may be defined, using these metrics in turn.

See http://www.is.reading.ac.uk/people/G.Haworth.htm if you want to read more,
esp. '6-man Data and Strategy'

g



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.