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Subject: Re: Diminishing returns

Author: rasjid chan

Date: 22:26:15 04/29/04

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On April 29, 2004 at 11:25:47, Robert Hyatt wrote:

>On April 29, 2004 at 03:13:07, Tony Werten wrote:
>
>>Hi all,
>>
>>a while ago we had some discussions about diminishing returns in search for
>>chess.
>>
>>My opinion was that you can't prove that with programs searching d vs d+1 ply
>>depth because the advantage of the d+1 program gets smaller. ie at d=1 it has a
>>100% depth advantage, at d=2 it's 50% etc.
>>
>>Some people claimed that you can't compare it that way because bla bla
>>exponential something bla :)
>>
>>Well, I found an easier way to explain it.
>>
>>A few assumption:
>>
>>The easiest way to win is when you see a trick, your opponent doesn't see.
>>
>>The depth that needs to be searched to see a trick is equally divided. ie there
>>are as many tricks hidden 1 ply away as there are tricks at 2 ply ( it doesn't
>>really matter but it's easier to visualize )
>>
>>w is player d+1
>>b is player d
>>
>>d=1: b sees tricks 1 ply away, w sees ply 1 and 2 => w sees 2.0x as many tricks
>>d=2: b:1,2 w:1,2,3 => w: 1.5x
>>d=3: b:1,2,3 w:1,2,3,4 => w: 1.3x
>>...
>>d=10: b: 1..10 w: 1..11 => w:1.1 x
>>
>>
>>
>>Conclusion: There may or may not be diminishing returns in chess, but d vs d+1
>>are not going to prove it, because those matches by itself are a clear example
>>of diminishing returns regardless what game is played.
>
>That is all well and good.  But the fact remains that D+1 is _always_ better
>than D.  How much better really doesn't matter, IMHO.  Just the fact that it is
>better makes it worthwhile...

I have a question which I'm not sure relates to diminishing returns.

You posted in the past that Crafty don't evaluate pins and you
mentioned something about depths... nowadays .. reaching 12/14 plys...
I think your reasoning was invalid.

Searching deeper clears 1 pin but then there is the next.. and the next.
So even if we search till 24 plys, if eval pins is beneficial, it will
be beneficial at whatever plys we reached even with super hardware.

Hope not triple dumb move!

Rasjid

>
>
>
>
>>
>>disclamer: I know chess isn't only about tricks, but it is an advantage to see
>>more of them then your opponent. Clearly the win percentage is depending on
>>other (random) stuff as well. BUT When you see less more, the advantage becomes
>>less.
>>
>>Tony



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