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Subject: Re: Side effects of lazy eval?

Author: Carlos del Cacho

Date: 09:27:09 09/28/00

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On September 28, 2000 at 00:18:58, Robert Hyatt wrote:

>On September 27, 2000 at 12:10:00, Carlos del Cacho wrote:
>
>>On September 27, 2000 at 09:26:45, Robert Hyatt wrote:
>>
>>>On September 27, 2000 at 07:47:18, Bas Hamstra wrote:
>>>
>>>>Supposing no "lazy-errors" at all were made, does anyone know if there are
>>>>serious side-effects to lazy eval?
>>>
>>>None at all.  Except that guaranteeing this is a bit hard.  :)
>>>
>>>
>>>
>>>>
>>>>I one experiment that I yet have to repeat, it seems that NPS increases, but
>>>>Depth (as averaged over 300 wac positions) does not.
>>>>
>>>>I would like to know if others have seen alike or other problems with LE.
>>>>
>>>>
>>>>Regards,
>>>>Bas Hamstra.
>>>
>>>It has been used forever.  As a classic trade-off between speed and accuracy.
>>
>>Just a question related with this. Since I implemented lazy eval in my program I
>>don't store the value returned by search in the hash table when there's a fail
>>high or a fail low. I just store beta or alpha instead. Is this correct ?
>>
>>Thanks in advance,
>>Carlos
>
>
>That is one way to do it.  Storing values outside alpha/beta (referred to as
>fail-soft alpha/beta) also works...

Yes, that was the approach I used before. But it seems to work worse now.
Suppose I get to a node where lazy eval gets applied. Backing up the tree I have
no idea it did so. Suppose I fall high. I can't store this score as a low bound
on the true score unless I store some info of the window used, because if
researched with other alpha-beta window score can get lower than this.
I'll keep thinking about it.
Carlos



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