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Subject: Re: razoring in crafty version 16.9, mid 1999

Author: Gian-Carlo Pascutto

Date: 09:43:47 08/22/02

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On August 22, 2002 at 11:13:46, Robert Hyatt wrote:

>If you don't see the difference, pick up any good AI book.  Most all cover
>it.  Reducing the depth is reducing the depth.  It is not the same thing
>as saying "I choose to throw this move out at this ply and not even consider
>it at all".  razoring says "this move looks suspiciously bad.  Rather than
>just throwing it out, I am going to search it to a 1-ply reduced depth, so that
>if it _does_ do something good, I will have a chance to see it with the reduced
>search."

Which is exactly the same thing.

Pruning cuts the move you apply it to. Razoring cuts the frontier moves below
the subtree your razor.

>Forward pruning will result in outright blunders.  By pruning a single move
>you miss the fact that that move kills you.  Or kills your opponent.  Even
>if the threat is very shallow.  Razoring doesn't hide the shallow threat at
>all, which is the point...

Razoring does hide the 'shallow threats' at the moves it *prunes* (which are not
the same as the ones you apply the razoring to).

--
GCP



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