Author: Robert Hyatt
Date: 18:38:29 06/02/98
Go up one level in this thread
On June 02, 1998 at 17:05:55, Komputer Korner wrote: >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 two reasons. #1 crafty does *not* suffer from many fail-lows. On a bad day it may lose 3-4 games. out of several hundred played. So it doesn't happen very often. #2 these things become permanent hash table entries, yet they are almost *never* seen. I don't want the hash table to be overflowed with crap that will almost never be seen again...
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