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Subject: Re: Any luck with ETC (Enhanced Transposition Cutoffs)?

Author: Tony Werten

Date: 01:43:31 08/04/01

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On August 03, 2001 at 16:56:08, Artem Pyatakov wrote:

>Has anyone here had any luck with Enhanced Transposition Cutoffs in their
>program?
>
>Just out of curiosity (and ease of SLOW/SIMPLE implementation of this idea), I
>decided to try it.

I've tried it. After normal hash lookup, before nullmove. Just generate all
moves, makemove, lookup, unmake. I just took cutoffs if the score had an exact
flag, because I got to confused.

ie The score must have an above_beta flag and -score has to be <=-alfa (or
something).

Didn't notice any (overall) improvement.

Tony

>
>The way I implemented it (just as a test), is by increasing move ordering
>"priorityScore" for successor moves that promise a cutoff and thus trying these
>moves first (but after the hash move).  But for some strange reason, I can't
>even get it to marginally reduce the number of nodes.
>
>This does not make sense to me, since I think that:
>1) It's supposed to reduce the number of nodes at least somewhat
>2) The reason most do not use is because the number of nodes that it eliminates
>trades off with the computational time, NOT because this approach does not work
>completely.
>
>Any ideas? suggestions?
>
>Thank you.
>
>Artem



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