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Subject: Re: ETC

Author: Bas Hamstra

Date: 16:17:52 08/17/99

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On August 17, 1999 at 13:37:37, Andrew Williams wrote:

>On August 17, 1999 at 11:18:05, Dan Homan wrote:
>
>>Do any programmer's have experience with Enchanced Transposition Cutoffs?
>>It seems to me that these would be a fair amount of work at each node, but
>>I was wondering if people generally find the payoff to be worth it.
>>
>> - Dan
>
>I've tried it twice in my program and both times found it unhelpful.
>I think it might do better in my program if I tried a stripped-down
>make_move, because I don't need (eg) my incremental updating of attack-
>tables for the ETTC test.
>
>Andrew Williams

Andrew, that's very interesting that you mention that incremental attacktables.
I've been doing that for a long time (pseudo attacks, ie blocking pieces
ignored) and achieved reasonable speed. About on par with Crafty. It gives a lot
of handy advantes, both in capture generation (plus easy SEE) and eval. For
every square of the board each of the 32 attackbits represented the attacking
piece.

I too stripped and redid my make/unmake. You can't ever go faster than the
make/unmake, how fast it may be. In fact I redid everything and spent a whole
vacation experimenting. I just now made a breakthrough in figuring out which
datastructures are fastest for capture- and attackgeneration. I hope to be able
to tell more soon. Occasionally ideas work in practice too :)


Regards,
Bas Hamstra.










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