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Subject: Re: Results of John Merlino's Chessmaster survey?

Author: John Merlino

Date: 18:18:59 11/30/01

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On November 30, 2001 at 18:36:58, Jason Williamson wrote:

>Surely that time could be improved?  Or is it still memory issues as the major
>problem?

Definitely memory issues. The import that Chessmaster uses (which, admittedly is
quite ancient and nobody really wants to touch it) is rather slow. But the
problem is the memory requirements. A lot of time could be spent on optimization
and so forth, but it is hard to justify it with regards to the schedule,
considering that the feature is probably used by only 0.01% of our users (if
that!).

During import, each node requires 43 bytes of data. This adds up very quickly
when you're talking about 40 moves each of 140,000 games. Worst case scenario
(which isn't actually possible, as there have to be SOME repeated moves) would
be over 240 million bytes of RAM required.

I did spend a fair amount of time (i.e. a couple of days) trying to improve
things, and this was the result. The original code (written long before I got on
the scene) required 92 bytes of data per node. But it wasn't a problem because
the format limited a book to a maximum of 64K moves. So the maximum memory usage
for the old format was only about 6MB -- not a big deal.

If I felt like spending a couple of weeks, things might be improved noticeably.
Unfortunately, I don't feel like it! (and don't have the time even if I did feel
like it).

Hopefully, the quality of the new book will make it so the opening book editor
is used even less!

jm



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