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

Author: Tony Werten

Date: 01:37:09 02/07/02

Go up one level in this thread


On February 06, 2002 at 13:09:27, William H Rogers wrote:

>On February 06, 2002 at 10:37:19, Sune Fischer wrote:
>
>>On February 06, 2002 at 10:19:29, William H Rogers 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.
>>>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.
>>>
>>>The diminishing returns issue is probably an effect of converging towards the
>>>ideal move as often as possible.
>>>
>>>-S.
>>>
>>>I vote for your analisis. Just for an example lets say that a program can only
>>>search to a level of 10 plys and it thinks that it has found its very best move,
>>>then lets assume that we can search 2 to 4 plys deeper and it discovers that
>>>there is a better move that can help it win the game. This happens all of the
>>>time in chess and in other zero-sum games. The deeper you search the better you
>>>game will be, of course it really depends on your evaluation routine is
>>>basically sound in the first place.
>>>Bill
>>
>>I agree, if we forget about chess programs and just study chess, then we can
>>ask:
>>
>>A:) What is the percentage of ideal moves that can be found at ply 0 ?
>>B:) What is the percentage of ideal moves that can be found at ply 1 ?
>>C:) What is the percentage of ideal moves that can be found at ply 2 ?
>>D:) What is the percentage of ideal moves that can be found at ply 3 ?
>>E:) What is the percentage of ideal moves that can be found at ply 4 ?
>>etc...
>>
>>Now obviously this percentage cannot be constant since it must sum to 1, so it
>>has to be descending which means diminshing returns.
>>Exactly what type of function that is I do not know, but it would interesseting
>>to find out :)
>>
>>-S.
>
>I think that there might be many different moves based upon which opening that
>was used by white, otherwise white might say e4 and mate in 58 moves. We have
>not reached that point in computer chess yet, but we certainly headed that way.
>Last year a major tournement was won by a program that never left its opening
>book.

We call this in dutch a sandwich ape story ( more or less) It's a story that
isn't true but sounds like it could be. Precise facts are always missing.

Which program, which tournement ?

Tony

>Bill



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