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Subject: Re: Is the Depth directly proportional to the program's strength? (YES!)

Author: Tony Werten

Date: 01:55:23 02/07/02

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On February 06, 2002 at 10:45:25, Sune Fischer wrote:

>On February 06, 2002 at 10:30:15, Tony Werten wrote:
>>>So it would seem, but the search is exponential and not linear.
>>>I think you should not consider the "depth" but rather the number of nodes
>>>searched.
>>
>>Doesn't make a difference. Depth and number of nodes are the "same".
>
>Not at all, nodes is an exponential function of depth.

Yes, should have said highly related.

My point is that when you give a program 1M nodes more than the other, at low
depths this might be a couple of ply, at higher depths, it's less than a ply.

Calling this diminishing returns isn't correct IMO. It's just the way a
searchtree works. I believe DR is the fact that 4-3 scores a bit better then 8-6
and 12-9


>
>>>If you go one ply deeper then (assuming your branch factor (BF) is not too depth
>>>dependent) you a factor of BF more nodes, this ratio is fairly constant so I'd
>>>go with Uri's definition.
>>
>>Ok, have it your way. in 4-3 you give BF/3BF advantage and in 5-4 you give
>>BF/4BF advantage.
>
>I do not understand your ratios, if you mean:
>nodes(ply n+1) ~= BF*nodes(ply n)
>then we agree.
>
>>The ratio is constant, but the added percentage isn't.
>>
>>New example: distance 100 miles.
>>10 Mph=> 10 h
>>20 Mph=>  5 h
>>30 Mph=>  3.3 h
>>40 Mph=>  2.5 h
>>
>>New paper. Diminishing returns in carspeed ?
>
>:)
>This is correct, but not related to our discussion.
>These are linear relations, not exponential.

OK. Hmm, how about giving a limited amount of petrol to accelerate a car ? If
the first car goes slow, you can go twice as fast and arrive a few hours befor
him. Else it might only be a few percent and a few minutes.

>
>>Tony
>>
>>>
>>>The diminishing returns issue is probably an effect of converging towards the
>>>ideal move as often as possible.
>>>
>>>-S.



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