Author: Carmelo Calzerano
Date: 08:35:10 02/19/01
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On February 19, 2001 at 09:55:04, Larry Griffiths wrote: >On February 19, 2001 at 06:01:36, Carmelo Calzerano wrote: > >>On February 18, 2001 at 11:29:39, Larry Griffiths wrote: >> >>>Hi, >>> >>>I use a reference indicator in my hash entries when the hash key matches. >>> >>>Only 20 to 40% of the hash entries are being referenced during a tree search. >>> >>>Is this a normal range? >> >> >>Surely not, unless the number of entries in the table is much bigger than the >>number of nodes you visit in the search (which is usually not the case). I have to correct myself: 40% is _not_ a bad value, unless the number of nodes visited is much bigger than the number of hash entries :-) >>Hash entry references must be equally distributed; i.e., if you have a 1 M >>entries in your hash and search 100 M nodes, you should find each hash entry >>referred about 100 times (with small statistical fluctuations of course). >> >>HTH >I used Bob's Random64() function to produce the Hash keys. I also created two >hash tables so that black and white positions would not overlay each other. >I even use slots and will do a hash add within the next 7 slots if the primary >hash slot add fails. But what's the ratio between nodes visited/hash size? I.e., if you have 1 M hash entries and visit 5 M nodes, 20-40% sounds ok. OTH, if you have 1 M entries but visit 500 M nodes, then 20-40% is _definitely_ a very bad value... :-) >It may be that positions that caused cutoffs are never seen again because >succeeding cutoffs occur. I'm not sure I understand what you mean Bye, Carmelo
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