Author: Dann Corbit
Date: 15:45:42 01/31/02
Go up one level in this thread
On January 31, 2002 at 17:54:14, Uri Blass wrote:
>On January 31, 2002 at 16:34:52, Dann Corbit wrote:
>
>>On January 31, 2002 at 16:19:51, Uri Blass wrote:
>>
>>>On January 31, 2002 at 14:36:04, Dann Corbit wrote:
>>>
>>>>On January 31, 2002 at 14:31:38, David Rasmussen wrote:
>>>>
>>>>>On January 31, 2002 at 13:13:57, Dann Corbit wrote:
>>>>>
>>>>>>On January 31, 2002 at 06:58:28, David Rasmussen wrote:
>>>>>>[snip]
>>>>>>>>Just like "ply" means 20 different things to 20 different programmers. Even
>>>>>>>>"nodes" does not always mean the same thing.
>>>>>>>>
>>>>>>>
>>>>>>>Agree with you on nodes, but ply? Ply is pretty well defined, I think.
>>>>>>
>>>>>>For sure it is not. In fact, even when we agree, we disagree. Every single
>>>>>>chess program will have a tree of a different shape. So even when we count
>>>>>>plies the same way, the actual search can be incredibly different (with the
>>>>>>number of nodes visited differing by several orders of magnitude). Compare, for
>>>>>>instance, Mchess with Goliath.
>>>>>>
>>>>>>Junior [for instance] does not count plies the same way as other programs.
>>>>>>
>>>>>>Ply is ill defined. In fact, I think it is actually impossible to define it
>>>>>>accuracy, except in the brute force sense. And absolutely nobody exhausts a ply
>>>>>>when doing chess games with an engine.
>>>>>>[snip]
>>>>>
>>>>>That is bull. A ply is a half move and that is that. What you are talking about
>>>>>is: what does it mean when we say a program searches 8 ply? Of course if that is
>>>>>the question, the answers are as many as there are programs. But in this thread
>>>>>we are talking about a full width alpha-beta tree (at least, since DB had
>>>>>singular extensions, which requires extra searches), of some fixed depth search
>>>>>in a given program (that is, move ordering and evaluation forms the tree).
>>>>
>>>>I suggest that you lookup with the CCC search engine the dozens of posts that
>>>>shot *ME* down when I tried to insist that a ply is a ply is a ply.
>>>>
>>>>The thorough and convincing arguements against it showed that I was clearly
>>>>wrong.
>>>>
>>>>As you are clearly, unmistakeably, and totally wrong right now.
>>>
>>>He is not wrong if we talk about full width alpha beta.
>>
>>Which is the same as saying "If we all wore giant balsa-wood shoes, we could
>>walk on water."
>>Nobody wears them, as far as I know.
>>
>>There is no chess program on the planet that does that. (Except -- of course --
>>for the rankest sort of amateur program).
>
>No commercial program but it does not mean that deeper blue did not do it.
>I agree that plies do not mean the same for top programs but the discussion is
>about deeper blue and not about the top programs.
>
>
>Thanks to posts of Ed and Andrew
>It is known that deeper blue searched deep force depth of only 12 plies and the
>reason that they searched only 12 plies was the fact that they used more
>extensions than the top program of today.
>
>other programs do not use brute force and use less extensions so 12 plies of
>deeper blue are usually more than 12 plies of other programs.
>
>My opinion is that 11-12 plies that were searched by deeper blue may be
>eqvivalent to 13-14 plies of Crafty.
But then you are invalidating your own argument that a ply means the same thing
everywhere. Or at least with pure alpha/beta {which is obviously not what was
used then}
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