Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: GM Smirin vs 4 comps - Match Predictions

Author: Walter Koroljow

Date: 07:48:03 04/17/02

Go up one level in this thread


On April 17, 2002 at 09:15:56, Chris Carson wrote:

>On April 17, 2002 at 08:08:56, Walter Koroljow wrote:
>
>>On April 16, 2002 at 21:13:40, Miguel A. Ballicora wrote:
>>
>>>On April 16, 2002 at 18:34:57, Walter Koroljow wrote:
>>>
>>>>Of course you can combine TPRs of different programs as per common sense.
>>>>
>>>>However, if you wish to be mathematically absolutely correct and precise, all
>>>>you need do is say, "The average of the programs' TPRs is ...".
>>>>
>>>>A little algebra will quickly show that the the average of the programs' TPRs is
>>>>exactly the TPR of the programs taken as a group.  This change of wording gives
>>>
>>>Actually, that is not correct.
>>>
>>>Regards,
>>>Miguel
>>>
>>>
>>I believe it is correct.  Here is a simple example: two programs play a human
>>rated 2700. Program 1 wins and program 2 loses.  then:
>>
>>TPR1 = 2700 + (wins-losses)*400 = 2700+400 = 3100
>>TPR2 = 2700 + (wins-losses)*400 = 2700-400 = 2300
>>Average of two TPRs = (2700+400 + 2700-400)/2 = (2300 + 3100)/2 = 2700.
>>
>>Notice that this is just 2700 + average of 400*(wins-losses).
>>
>>On the other hand, the "team" TPR is:
>>
>>2700 +(wins-losses)*400/2 = 2700 + (1-1)*400/2 = 2700. **
>>
>>This is also just 2700 + average of 400*(wins-losses).  **
>>
>>This illustrates the general case:  in both cases the (wins-losses)*400 term is
>>averaged over all games.  Hence the same answer.
>>
>>Best regards,
>>
>>Walter
>
>This shows the spread 2300 to 3100 with a 2700 average.  Nice simple example.
>
>You left off the "/2" in your last two examples (check right hand side of "=" in
>the next to last example, I put ** next to each).  This did not make a
>difference since the "win-loss" was 0, but would if that were not the case.
>

Well, we are both half-right!  I left off the /2 in the first statement, but the
word "average" implies the /2 in the second statement.

By the way, congratulations on your degree and your new profession.  Best of
luck to you.
>>
>>>
>>>
>>>>you an unassailable mathematical position.  And I think the common sense meaning
>>>>is not changed.  If you don't want to bother with this distinction, I won't
>>>>mind. :)
>>>>
>>>>Cheers,
>>>>
>>>>Walter
>>>>
>>>>P.S. Chris - When you say TPR, it would be nice to say whose TPR - Smirin's or
>>>>the programs'.



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.