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Subject: Re: HashTable upper_bound worthless ?

Author: Carmelo Calzerano

Date: 05:55:23 02/13/01

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On February 13, 2001 at 06:09:02, Larry Griffiths wrote:


>It looks more like this, Bob.
>BestScoreSoFar=alpha
>
>for(do capture moves)

[snip]

>   return BestScoreSoFar;


(It seems to be ok)

>>>I see all three types added to my hash table, but it seems that the
>>>upper_bound entries never cause any cutoffs to occur when searching
>>>the hash table.
>>>
>>>If I do not add lower_bound hash table entries, then I see some
>>>upper_bound cutoffs occuring.  It acts like the upper_bound entries
>>>get overlayed so often by lower_bound entries so that they never
>>>get seen when searching the hash table.
>>>Is this normal, or is something wrong with my code?

I guess it's normal, although you should definitely see some upper_bound
cutoffs from time to time. Matter is that the number of fail-high nodes
(which stores lower bounds in the HT) is usually about one order of magnitude
_bigger_ than the number of fail-low nodes visited in search; so upper_bound
HT entries are often replaced by lower_bound ones.

So it should be normal, IMHO, if lower_bound cutoffs occur more often (say
10 times, for example) than upper_bound ones; but the number of upper_bound
cutoffs should not be zero anyway...
:-)

Bye,
Carmelo



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