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Subject: Re: Position-Based

Author: Komputer Korner

Date: 14:05:55 06/02/98

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On June 02, 1998 at 15:24:35, Robert Hyatt wrote:

>On June 02, 1998 at 14:02:13, Roberto Waldteufel wrote:
>
>>
>>On June 02, 1998 at 08:09:12, Robert Hyatt wrote:
>>
>>>On June 02, 1998 at 03:21:38, Stuart Cracraft wrote:
>>>
>>>>So what I hear is that having position-based "learning"
>>>>is something like saving the position after a really bad
>>>>drop in the iteration of a score in the hash table with
>>>>a special flag. When the game ends, write out all
>>>>such entries to a disk based file. When restarting
>>>>the program, read in the disk based file into the
>>>>hash table and set the flags. When searching, if
>>>>the position turns out to be one of those positions,
>>>>then what?
>>>>
>>>>I could dig out my Slate (one or the other forgot which)
>>>>article in ICCA on the "Mouse" program -- is that essentially
>>>>what this Position-Based "Learning" is that some
>>>>programmers are using to create artificial wins against
>>>>other programs? If so, any big refinements to Slate's method
>>>>for the current crop? If no, what are the major differences
>>>>between Slate's method and the current vogue?
>>>>
>>>>Thanks,
>>>>--Stuart
>>>
>>>
>>>all you have to do is write the hash entry out when the score drops, and
>>>reload it before each move from then on, or (as I do) load them once and
>>>flag them as "permanent".  That is all you do.  Hashing will take care
>>>of
>>>the rest, and you will see the "trouble" several plies earlier the next
>>>time you play the same game, and you will play a different move to avoid
>>>reaching the position where the score is going to drop.
>>
>>
>>Can you clarify this for me - do you keep a permenant file of "bad"
>>positions that you add to with each game played? if so, is there not a
>>risk that eventually the file of permenant positions may become so large
>>as to clog up the hash table with positions that may be irrelavent to
>>the current game? Or is the nimber of stored permenant positions too
>>small to present any problem of this kind. Also, if you make a
>>modification or improvement to the program, then do you have to start
>>from scratch with the permenant positions, or do you just assume that
>>the improved version of the program will misjudge the same positions
>>that it misjudged before, and so leave the permenant position file
>>unchanged?
>>
>
>my position file has 65536 entries, and is "wrap-around" once it fills
>up in a FIFO ring buffer.  However, I *never* let it fill up, because I
>delete it regularly.


why isn't this larger?

--
Komputer Korner



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