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Subject: Re: incremental attack tables?

Author: Gerd Isenberg

Date: 03:52:06 05/05/04

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On May 05, 2004 at 03:03:15, Daniel Shawul wrote:

>Hello
>
>Is incremental attack table slower than creating them on fly?
>I have both versions working properly right now but the incremental
>one further drops NPS by 30% , though InCheck and Checks are for free in this
>case. Anybody have similar experience? I am sure i have made no mistake in
>updating because i checked it with the known perft positions and node count is
>perfect.
>
>best
>daniel


Incremental attack table update in one stage has probably (depending on your
design and structures) the drawback, that it is done in make/unmake, even if
those moves result in "lazy" (leaf) nodes, where most attack information is not
needed at all.

Another aspect with incremental attacks is that the amount of work depends on
the number of squares with changed controls. So IMHO programs that do
incremental attack generation probably become relative weaker in some endings
with sliding pieces.

Gerd



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