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Subject: Re: Faster, deeper and more of such...

Author: Vincent Diepeveen

Date: 20:32:43 09/15/00

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On September 15, 2000 at 03:11:22, Uri Blass wrote:

>On September 14, 2000 at 13:42:49, Ed Schröder wrote:
>
>>In the upcoming Rebel Century 3.0 I have implemented a little
>>statistic routine that reveals something about the nature of SEARCH
>>that could be important for the future of computer chess in the sense
>>that it says "something" one may expect in the near future because
>>of faster and faster PC's.
>>
>>Research on this issue have already been done by Bob and Ernst and
>>it has made me curious so I have spend a little time on it. The
>>statistic shows 2 things:
>>
>>a) number of fail-low's for each depth;
>>b) number of "changed moves" for each depth.
>>
>>(a) is not so important as often fail-low's do not mean anything but I
>>wanted to know anyway.
>>
>>(b) is extremely important as it shows for each depth how many times
>>Rebel changed its mind. As you can see in the below statistic the %
>>diminish and diminish the deeper Rebel goes.
>>
>>How to read the overview:
>>- first column: iteration depth;
>>- second column: number of times the depth was reached;
>>- third column: number of fail-low's;
>>- fourth column: percentage of fail-low's;
>>- Fifth column: number of changed moves;
>>- Last column: percentage of changed moves;
>
>1)I think that the interesting question is if there is a diminishing return from
>time and not if there is a diminishing return from plies.
>
>I think that the following data may be interesting when you use fixed time of
>2^n seconds per move(you can choose n)
>column 1:number of changed moves between 1 seconds and 2 seconds
>column 2:number of changed moves between 2 seconds and 4 seconds
>column 3:number of changed moves between 4 seconds and 8 seconds
>
>column n:number of changed moves between 2^(n-1) seconds and 2^n seconds

You're using a power of 2 here to measure where the branching
factor hardly will have a power of 2, so you're falsifying research
by using time measurements using a power of 2.

Of course the whole idea to measure principle variation changes
i find complete nonsense in advance, but if you measure it, then
measure plydepth based, not second based!

>2)You can use the same idea without fixed time in normal games  when you have
>also column for the number of cases that you used at least 2,4,8...seconds but
>in this case I expect the last column to have relatively more changes because
>you use more time when you fail low and the small number of cases are not random
>positions.
>
>In this case column 1 should be read like this:
>The number of changed moves between 1 seconds and 2 seconds out of the cases
>that you used at least 2 seconds.
>
>In this case there should be also more columns of the number of cases that you
>used at least 2 seconds(4,8,...).
>
>Uri



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