Author: Tony Werten
Date: 00:17:34 03/26/03
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On March 26, 2003 at 02:57:04, Tony Werten wrote: > >On March 25, 2003 at 17:30:52, martin fierz wrote: > >>i computed some checkers endgame databases with retrograde analysis based on the >>paper by the chinook team. for larger databases, i have a memory size problem; >>specially as win32 only allows a process to use 2GB. >>i once heard that it was possible to compute a win/loss/draw endgame database >>using only 1 bit per position as opposed to 2 bits as i was using up to now (and >>like in the chinook paper). > >The only way I know of doing this is make an assumption about the position. If >on side has an advantage you could use win/no win. With "no win" you don't care >about wether it's a draw or a loss. It's the wrong path anyway. ( Or the right, >depends on whose move it is ) > >The only thing you need is a "decisionmaker" when the weaker side has 2 "no >loss" moves to decide wich is best. ( ie 1 might be a draw and 1 a win ) Solution: Make 2 tables: white to move, black to move. Use only win/no win. If a move is a no win, find all successor in the "opponent to move" table. If opponent has a win, the original position is a loss else it's a draw. This takes extra time but isn't nescessairy to do very often; only when the current position is in the pv. (ie beta-alfa != 1 ) Tony > >Tony > >> >>does someone here know more about this? i'm looking either for an explanation >>for dummies, or for a reference to a paper. >> >>thanks in advance >> martin
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