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Subject: Re: new thoughts on verified null move

Author: Robert Hyatt

Date: 07:48:52 11/24/02

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On November 23, 2002 at 13:38:32, Josť Carlos wrote:

>On November 23, 2002 at 12:53:36, Omid David Tabibi wrote:
>>>Nodes to solution should be a better parameter.
>>Provided that you have a pool of positions that can be solved within a
>>reasonable time!
>  You should find them to provide useful data. Tree reduction doesn't mean
>anything if the solution is not found. Nodes to solution is definetly the
>important data.
>  Josť C.

Maybe I am overlooking something, but as best I could tell, his new algorithm
solved more positions than R=2, at the same depth.  _and_ the tree was smaller.
I don't see how that can be considered a bad way of reporting things.  He ran
to fixed depth, which I personally think is very reasonable since it provides
something that can be repeated.  He reported the sizes of the trees, which shows
that his approach searches a smaller tree than straight R=2.  And he provided
the number of correct solutions showing that his approach is better than
straight R=2 also.

To consider his data invalid, you would have to assume one of the following:

1.  His positions are _all_ zugzwang positions, so that any zugzwang detection
would make it perform better than straight null-move R=2.

2.  Somehow his search makes searching the PV much harder, and the non-PV moves
much easier, so that reporting the time to solution would somehow show larger
numbers for his new code, even though the time to complete a depth is lower.
(I assume the time to depth is lower since he used the same program for both
and I don't think his NPS will be affected by the algorithm significantly).

I find either of those to be a bit hard to accept, and I concluded that what
he did worked for him.  Whether it will work for the rest of us or not is
another thing...

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