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Subject: Re: To anyone who has ever automatically created an opening book

Author: John Merlino

Date: 13:19:23 11/13/01

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On November 12, 2001 at 15:52:25, Scott Gasch wrote:

>On November 09, 2001 at 20:25:52, John Merlino wrote:
>>
>>To give a quick answer:
>>
>>My test was with a book with just under 150,000 games in it. It took about 250MB
>>of RAM (which ended up requiring about 100MB of swapping on my machine), and a
>>little less than 4 hours to process at a depth of 40 plies. The result (after
>>pruning zero-weight branches, which is, in effect, the same as your "straining"
>>process) was a file that was about 550K. If I had not pruned the zero-weight
>>branches, the file would have been about 6.1MB. Admittedly, though, this timing
>>is during a debugging process, and I have not actually tried running it with a
>>release build.
>
>What is taking it so long?  Is it swapping?  That will kill the speed of book
>generation, of course.  Is the PGN reader just really slow?  Have you tried
>profiling the code during book generation?  It might give you an aha.
>
>>However, I think our PGN reader code is one of the main bottlenecks. It appears
>>to only be able to import about 100 games/second, and nobody else has reported
>>anything less than 2,000 games/second. That's probably something I should look
>>at.

It's DEFINITELY the PGN reader (which is very old and VERY picky code, meaning
that I am reluctant to change any of it). It appears to average 15-20ms per
game, which is why I'm only getting about 60 games/second total speed during
import.

Oh well.... According to my survey, there's probably only about 100 people who
actually use it (and I'm only half-kidding).

jm



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