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Subject: Re: To build a book or not?

Author: martin fierz

Date: 13:42:47 07/16/02

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On July 16, 2002 at 16:20:30, Russell Reagan wrote:

>On July 16, 2002 at 15:14:17, Omid David wrote:
>
>>Each program has its own style and thus should play openings which fit its
>>style. Of course these openings should be tuned by the programmer, so a good
>>deal of chess knowledge is necessary on programmer's behalf.
>>
>>As an example, in tournaments I always play Sicilian against 1.e4 and adopt the
>>Scheveningen variation, so I need to have a vast knowledge of Scheveningen (and
>>Najdorf) while I can forget about Caro-Kann! Programs too should have their own
>>opening repertoire consisting of an extensive knowledge of all variations which
>>might occur in their chosen opening variations, while they can forgo other
>>variations.
>>
>>Omid.
>
>Thanks Omid. I have another question. Let's take an example. Let's say that my
>program has a Ruy Lopez line that goes to move 20, and then the book stops
>there. Would it be advantageous to let my program think from that position for,
>say, a week, and then add that move to my book? That way I have a week's worth
>of search instantly.
>
>The only thing that I forsee as a problem is the same problem that a beginner
>who memorizes book lines has. For example, let's say my program plays the last
>move in the book (the one that was searched on for a week), and it plays it, and
>my opponent responds, and then my program doesn't have access to the long
>variation that it had in the week long search, so now my program *might* (not
>sure about this) be just like the booked up beginner who doesn't know what to do
>when it leaves the book. For example, the program might need to search to 20
>plies to "see" the reasoning for it's previous move, and if it can only get to,
>say, 16 plies in the given time slot in a game situation, it might not follow
>that PV line. Do you see this as something that might be a problem?
>
>Thanks,
>Russell

yes, what you describe is certainly a problem. i generate the opening book for
my computer checkers program automatically, with the engine calculating
positions and adding them to a database. i usually just use a tournament time
control level to search a move, because doing shallower searches can hurt you
because the book move is worse than what you would see on a normal search, and
doing deeper searches risks not finding the necessary follow up. it makes much
more sense to expand your line with something like 240 5-minute searches instead
of 1 12-hour search. you get many more book moves, and since you back up scores
from later searches to the root, you have a similar kind of quality for the
first move in your computed book as if you had searched for 12 hours there.

aloha
  martin



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