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Subject: Re: Dann, question

Author: Russell Reagan

Date: 22:53:24 11/21/03

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On November 21, 2003 at 22:18:38, Christophe Theron wrote:

>It is possible that this advice would not work for another chess program, for
>example one that "clears" its hash table before it starts thinking. In this
>case, clearing 1Gb of hash table when playing bullet games would lead the
>program to use almost all its time for "clearing the hash table". Really dumb.

I think this is what Johan does, if I recall correctly his postings here not too
long ago.

I'm not sure if he does this or not, but you could "clear" any sized table in a
single cpu cycle if you wanted, using a "dirty bit" concept. Of course, to be
accurate your "bit" would have to be multiple bits in reality, which would take
up more space in your hash entry, but an extra byte is worth it if you want to
"clear" the entire table while using as much memory as possible. Besides, if you
are going from 32MB of hash table memory because of clearing limitations to
128MB, 256MB, or more, then the extra byte results in a huge gain.



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