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Subject: Re: stuffing moves in hashtable, fail low

Author: Inmann Werner

Date: 23:50:01 11/30/99

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On November 30, 1999 at 20:04:00, Gerrit Reubold wrote:

>On November 30, 1999 at 18:26:27, Inmann Werner wrote:
>
>>Since some time, I do the following.
>>
>>when I am in the loop in alpha-beta, trying all moves of a position and find a
>>new bestmove I do not stuff it in the hashtable (what others normally do?). I
>>look at all moves till all searched or a cutoff occurs. Then I stuff only the
>>cutoff or best move in the hash.
>>
>>Difference is, that i only stuff in hash one time and i do not have a "best move
>>so far" in the hashtable.
>>In my prog it works some better then the "normal" method.
>>
>>Has anyone tried this also?
>>Did I miss something in my idea? (don´t think so, cause it works well..)
>>
>>Werner
>
>Hi Werner,
>
>I do the same (in Bringer) as you do, however, I consider "our" way to be the
>standard way! If you store "best-so-far" moves, it would make little difference;
>those HT entries will be eventually overwritten by the best move anyway.
>Two Months (?) ago we had a thread "what should we store if all moves fails
>low?" with the answer: Nothing! There should be a saving of a few percent of
>treesize if you don't store "random" moves in the HT. Maybe this could be an
>improvement of your algorithm?
>Hope this makes sense.
>
>Greetings,
>Gerrit

Hello Gerrit,Bob.

I am astonished, that "my way" is the normal way cause it was "invented" by me.
Another thing of inventing old stuff new.....

With "best so far" moves, I needed 2% to 5% more nodes. Do not know why..

Why stuff in nothing at fail low?
fail low is bad for move ordering, so I do not use it there. Ok.
But for normal hashing, I use fail low, if the value<alpha. At mate values, I
give back something like mate in 500....(brings my prog to sometimes not show
right "mate in #", bothers me not much)
I overwrite fail low values first, cause they are the "less value" entrys.
Why should I search all moves, only to recognize, that it again is a fail low?
I see nothing good in it.

Werner



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