Author: Christophe Theron
Date: 11:45:30 07/16/00
Go up one level in this thread
On July 16, 2000 at 06:34:46, blass uri wrote:
>On July 16, 2000 at 03:34:45, Ed Schröder wrote:
>
>>>posted by Dann Corbit on July 15, 2000 at 20:21:54:
>>
>>>Simplifying. I have a penny.
>>>I toss it twice.
>>>Heads, heads.
>>>I toss it twice
>>>Heads, heads.
>>>I toss it twice
>>>Tails, heads.
>>>I toss it twice
>>>Heads, tails.
>>
>>>I count them up.
>>
>>>Heads are stronger than tails.
>>
>>>My conclusion is faulty. Why? Because I did not gather enough data.
>>
>>Right.
>>
>>A few months ago Christophe posted some interesting stuff here regarding
>>this topic and nobody really was in agreement with him (me included) until
>>I did an experiment which worked as an eye opener for me. The story is not
>>funny and goes like this...
>>
>>In Rebel Century's Personalities you have the option [Strength of Play=100]
>>The value may vary from 1 to 100 and 100 is (of course) the default value.
>>
>>Lowering this value will cause Rebel to lower its NPS. This opens the
>>possibility to create (100% equal!) engines with as only difference
>>they run SLOWER.
>>
>>I was interested to know HOW MANY games it was needed to show that a 10%
>>faster version could beat a 10% slower version and with which numbers. So
>>I created two personalities:
>>
>>FAST.ENG (default settings) [Strength of Play=100]
>>SLOW.ENG (default settings) [Strength of Play=80]
>>
>>and started to play 600 eng-eng games with Rebel's build-in autoplayer
>>with pre-defined fixed opening lines both engines had to play with white
>>and black.
>>
>>The personality with as only change [Strength of Play=80] caused Rebel to
>>slow down with exactly 10% on the machine the marathon match took place.
>>Note that this value (80) may differ on other PC's in case you want to do
>>similar experiments.
>>
>>Here are the results of the 600 games played between the FAST and SLOW
>>personalities. The first 300 games were played on a time control of "5
>>seconds average". The second 300 games were played on a time control of
>>"10 seconds average".
>>
>>FAST - SLOW 162.5 - 137.5 [ 0:05 ]
>>FAST - SLOW 147.0 - 153.0 [ 0:10 ]
>>
>>The first match of 300 games at 5-secs looks convincing. A 54.1% score
>>because of the 10% more speed seems a value one might expect.
>
>I think that there may be a factor of luck in the choice of the opening.
>I think that in order to avoid this problem you can play 150 games with white
>and after it play 150 games with black with reversed colours.
That's what he did, read again.
>I think that in this case the chances of the slow version to win are smaller.
Nope.
>I think that 10% faster is about 8 elo better.
Something like that. I would say 10 points with my own formula.
>8 elo better suggests a result of 153-147 and simple statisics tells me
>that the standard deviation is about 7 points(I am not sure about the
>probability f wins and draws so the exact standard devation is not clear).
>
>It means that in 95% of the cases you will get something between 161-139 for the
>weaker player and 167-133 for the stronger player so both results are logical
>and not surprising.
Yes, I agree with your numbers.
No surprise, I said so some time ago but apparently nobody was interested...
>I believe that playing in reversed colours after half of the game reduce the
>standard deviation but I still think that 300 games are not significant even in
>this case.
I think playing the same openings with reversed colors does not change the
statistical margin of error, but as we are playing chess it sounds like a
logical thing to do.
And that's what he did.
Christophe
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