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Subject: Re: MTD(f) and hash table size

Author: Tord Romstad

Date: 04:24:46 08/18/03

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On August 17, 2003 at 15:08:12, Rudolf Huber wrote:

>On August 17, 2003 at 14:09:19, Tord Romstad wrote:
>
>>On August 17, 2003 at 04:27:06, Rudolf Huber wrote:
>>
>>>First scan you source files for occurences of alpha and beta.
>>
>>There are no alphas or betas left -- I rewrote search() and qsearch() from
>>scratch
>>when implementing MTD(f).  I only have the single parameter (gamma), like in
>>Aske Plaat's paper.
>>
>>>If you find any look hard and try to understand what you are doing there. In
>>>mtd(f) there ist NO alpha and NO real beta. All the things (lazy eval?)
>>>you do with alpha and beta are most likely wrong. Use the last score instead.
>>
>>What does the "last score" mean in the above sentence?
>
>Yes, sorry. I mean the score from the previous iteration.

I see!  Thanks for clarification.  This seems like an interesting idea;
I will take a look at it.  Currently I am experimenting with tricks based
on the values of the upper and lower bound in the search driver (an idea
suggested by Andrew Williams).  A disadvantage is, of course, that often
we only have one such bound.

>You can also that score for lazy eval.

Fortunately, I don't use lazy eval.  I am sure it would have given me a
lot of headache when combined with MTD(f).

Tord



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