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Subject: Re: Interesting result from SSDF

Author: Amir Ban

Date: 12:18:01 06/09/00

Go up one level in this thread


On June 09, 2000 at 10:33:33, Robert Hyatt wrote:

>On June 09, 2000 at 06:26:17, Amir Ban wrote:
>
>>On June 08, 2000 at 16:10:16, blass uri wrote:
>>
>>>On June 08, 2000 at 15:25:22, Amir Ban wrote:
>>>
>>>>Ok, here's my two cents:
>>>>
>>>>The most likely estimate for the game outcome is the overall match result
>>>>(33.5/41). The probability for any *particular* sequence of 10 games (say the
>>>>last 10) to be 10-0 is (33.5/41)^10 = 13.3%.
>>>>
>>>>If you want probability for any sequence anywhere, the probability is larger, as
>>>>you point out.
>>>>
>>>>If you suspect the 10-0 result, you can argue that the most likely estimate
>>>>should discount this result, so this gives you a probability of (23.5/31)^10 =
>>>>6.3%.
>>>
>>>If you use the most likely estimate
>>>The probability for 10:0 is smaller than (23.5/31)^10 because there are draws.
>>>
>>>The result was +20, =7.-4 so if you use the most likely estimate you get
>>>probability (20/31) for Junior to win
>>>7/31 for a draw and 4/31 for a loss
>>>
>>>(20/31)^10=0.012493... so the probability is less than 2%
>>>
>>>I ignored the fact that the white probability is different from the black
>>>probability but not ignoring it does not change much the result because you get:
>>>
>>>(10/15)^5*(10/16)^5 that is 0.012558...
>>>
>>>If you do not ignore the last 10 games and ignore the colours you get
>>>(30/41)^10=0.043992...
>>>
>>>Uri
>>
>>All right, you are right about the draws.
>>
>>My presentation of the problem was more complicated than necessary. Here is the
>>question in its simplest form:
>>
>>A match of 41 games concluded with 30 wins, 7 draws and 4 losses. It is unknown
>>in which order these wins/draws/losses occurred.
>>
>>Out of all possible permutations with the same result, what percent of the
>>permutations have a sequence of at least 10 wins ?
>>
>>This is clear cut question for the combinatorics gurus in this newsgroup.
>>
>>There seems to be gross difference of opinion about the result of this, so until
>>we get an answer, we can have an opinion poll about the result.
>>
>>My guess: 40%.
>>
>>Amir
>
>
>As I mentioned before, I am simply worried that reusing the engine over and
>over might be the problem.  IE if you just crank up two copies of crafty and
>let 'em play, over and over, if one breaks, it will remain broken and will
>likely lose every game (or nearly every game) from that point forward.
>
>Since I don't test like this, it is very possible...
>
>And that would explain a sudden string of 0's at the end...  and it would
>explain things if the 0's stop after a restart or another tester plays games,
>since he would start a new crafty.

Of course, that is a possible explanation for this otherwise incredible result.

Another possible explanation is that there is a bug in Junior that something
doesn't reset correctly and the engine starts playing stronger than intended,
and wins every game. I definitely need to look into that.

Amir





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