Author: Robert Hyatt
Date: 16:40:19 05/09/04
Go up one level in this thread
On May 09, 2004 at 15:06:30, Uri Blass wrote:
>I see that crafty is using the following commands:
>
>if (buffered >= SORT_BLOCK) {
> BookSort(bbuffer,buffered,++files)
>
>If I understand correctly the book of crafty is not one file but some files,
>when every file is not more that SORT_BLOCK positions.
No. One file broken up into 32768 "clusters". A cluster is all the hash
signatures with the same 16 left-most bits (same parent).
>
>I wonder what is the reason for it.
>I think that it is more simple to call booksort only one time, after I read all
>the book positions into an array.
Which would you rather sort? one million things at a time, 100 times total, or
100 million things once? Hint" 100M at once takes _way_ longer... I produce
separate sort files, then merge them back into one file. It was done for speed
of production...
>
>The only problem can be if the book is too big so there is not enough memory in
>RAM, but I think that it is not a practical problem with the hardware that you
>have.
People have used game databases of 20+ million games, at 100 moves (50 moves per
side) that is a _huge_ number of book positions. Won't fit into RAM. So a form
of disk sort is needed.
>
>Do you do it in order to support users with inferior hardware or to support
>bigger books (that you practically not need for better results), or is there
>another reason for it?
Inferior hardware. Or good hardware with huge PGN input. Etc...
>
>Uri
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