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Subject: Re: Side effects of lazy eval?

Author: Dieter Buerssner

Date: 08:41:50 09/28/00

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On September 28, 2000 at 05:00:59, Bas Hamstra wrote:

>On September 27, 2000 at 16:16:21, Peter McKenzie 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?
>>
>>You can't get the full benefits of fail-soft using lazy eval.
>
>I agree. This is the only factor I can think off too, you lose some bound info.
>
>Yet, I ran a couple of WAC tests at very short time controls, with and without
>LE. And kept track of the average depth that was reached. In that quick test
>NPS went up, but the average depth stayed the same!
>
>So it seems what you win in speed, you lose in bound info, net result zero? At
>least in this case. I will rerun it more accurately, at longer tc.

You might want to give the following idea a try. I think this could be called a
fail soft version of lazy eval:

    es = s + largest_evalscore[side];
    if (es < alpha)
      return es; /* fail hard: return alpha */
    es = s - largest_evalscore[xside];
    if (es > beta)
      return es; /* fail soft: return beta */

This should store better bounds in the hash tables.

-- Dieter





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