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Subject: Re: Researching after a deep fail low

Author: Miguel A. Ballicora

Date: 13:01:49 09/24/01

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On September 24, 2001 at 15:24:53, José Carlos wrote:

>  First, the context:
>
>  Last night I finished implementing pondering for the first time. As usual, I
>chose the easyest way to begin with, until I make sure I understand everything.
>  So I did it this way: after moving, I guess the opponent move (second of the
>pv), make it, and start thinking. When the opponent's move arrives, I unmake the
>guessed move, make the real move, and start thinking normally. I expected the
>program to get to the pondering depth due to the info in the hash table.
>  This worked fine most of the time, but when the ponder search failed low deep,
>the research didn't go straight to that point. Instead, it chose another move at
>the begginning (because it saw the bad move in the hash table) and went
>deepening slowly.
>  I was very disapointed with this behavior, but when I started playing on ICC,
>I saw a big rating increase. Actually, the explained behaviour turned out to
>work really good, as usually the program made a good move even with less depth.
>
>  Now the question:
>
>  Has this been tried in _normal_ search? I mean, restarting from the begginning
>after a deep fail low.
>  Is this it a mistake to do what I'm doing? If so, what are the drawbacks?
>
>  Thanks in advance,
>
>  José C.

I guess that in these cases Internal iterative deepening might help. If you
are not using IID (I am not, it is in my to-do list, that is why I say that I am
guessing) restarting from the beginning could be even better. That would be
like a IID all over the tree, but faster because the hashtable kept values
everywhere. Now let's wait for somebody who really knows somthing about this
answer your question :-)

Regards,
Miguel
PS: It looks like Averno will be stronger and stronger! Bravo Jose!





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