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Subject: Re: DB Chip will kill all comercial programs or.....

Author: David Eppstein

Date: 11:07:17 05/15/99

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On May 14, 1999 at 17:11:24, Robert Hyatt wrote:
>you would probably want to call it 'gamma'...  but it is really both.  Either
>the score is above 'gamma' or it is below 'gamma'.  Below and you fail low,
>above and it fails high...  very mtd-ish...

No, that's not right.

I posted the actual code from his thesis in another thread, but basically:
Take the usual code for alpha-beta.
Only pass in beta as an argument, let alpha be a local variable.
Since you don't have a passed-in value for alpha, just set it to -INFINITY at
the start of each recursive call.

The net effect is that you only get cutoffs from your parent's search, not deep
cutoffs.  Hsu claims this only loses a factor of 1.07 per level of search.



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