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Subject: Re: a question about some crafty book code

Author: Uri Blass

Date: 17:27:58 05/09/04

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On May 09, 2004 at 19:40:19, Robert Hyatt wrote:

>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...

I understand.

>
>
>
>
>
>>
>>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.

The question is if there is a good reason to use 20+ million games for getting a
better book and if 1 million is not enough.

hint:games of weak players or blitz games are probably not very productive for a
better book.

Uri



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