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Subject: Re: MTD(f)

Author: José Carlos

Date: 15:02:51 01/07/01

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On January 07, 2001 at 16:38:50, martin fierz wrote:

>hi,
>
>i just implemented an MTD(f) search for my checkers program instead of my usual
>PVS/NegaScout - it seems to be about same good. in my hashtable i only store the
>value and valuetype, and i noticed that in aske plaat's MTD(f) description he
>stores both upper and lower bounds in the hashtable. i couldn't figure out a
>reason to do this - can somebody enlighten me?

  I don't do MTD(f) in my program, but I can figure why it is useful to store
both bounds: in MTD(f), most of your searchs are null-window, so you are failing
high/low most of the time. So you'll get an exact value to store in very few
times, and you'll mostly need to know an upper and lower bound for the position,
in order to quickly fail high/low.
  Sorry if my english is not very good. I hope you understand what I mean.

  José C.

>i tried in vain to construct some
>sequence of null-window calls which MTD(f) might do where it would be of use to
>save both bounds, but maybe i'm just missing something simple here?!
>
>cheers
>  martin



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