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Subject: Re: lazy eval

Author: Gerd Isenberg

Date: 12:17:22 05/05/04

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On May 05, 2004 at 14:32:46, Vincent Diepeveen wrote:

>On May 05, 2004 at 09:13:29, Gerd Isenberg wrote:
>
>>On May 05, 2004 at 07:37:06, Vincent Diepeveen wrote:
>>
>>>On May 05, 2004 at 06:52:06, Gerd Isenberg wrote:
>>>
>>>>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.
>>>
>>>Gerd, Note that
>>>for lazy eval you do not need to do an expensive makemove + function call in
>>>your qsearch to lazy eval a node. You can do it the ply before, even before
>>>making the move. So you save out 3 expensive function calls to lazy eval.
>>
>>Yes, that's correct.
>>Pruning before calling qsearch (score + gain(move) + margin <= alfa) versus lazy
>>eval and beta cut. The goal is to avoid or minimize not necessary work.
>>Gerd
>
>Yes, but how can you score points with it in 2004+?

We'll see ;-)
Isn't it state of the art?
I consider some triggers and positional scores from parent nodes too.

>
>b.t.w. do you show up in the sunny Tel Aviv in 2004?
>

yep, already registered.
I received my vacation ok from my employer today.
I have to check for visa and passport now and to look for the flight.
Maybe via schiphol...

>I hear it will be great beach weather and 11 rounds swiss. I plan to go now.

see you,
Gerd

>
>>>>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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