Author: J. Wesley Cleveland
Date: 09:18:43 05/15/01
Go up one level in this thread
On May 14, 2001 at 15:47:47, Robert Hyatt wrote: >On May 14, 2001 at 14:51:16, J. Wesley Cleveland wrote: > >>On May 13, 2001 at 22:42:00, Robert Hyatt wrote: >> >>>On May 13, 2001 at 19:48:59, J. Wesley Cleveland wrote: >>> >>>>On May 12, 2001 at 20:41:23, Robert Hyatt wrote: >>>> >>>>>On May 11, 2001 at 16:50:28, J. Wesley Cleveland wrote: >>>>> >>>>>>Okay. With exact results, you only need the number of plies to the next capture >>>>>>or pawn move stored with each position to solve the 50 move rule problem. >>>>>>Repititions are a non-problem, i.e. if from position A, you know that position B >>>>>>is a forced win, *but* the win leads back through A, you would never choose to >>>>>>move to B, because you would already know there is a shorter win from A. >>>>> >>>>> >>>>>How would you _know_ that either of those positions were forced wins if you >>>>>don't save _everything_ as you search? >>>>> >>>>You know because you have a string of positions in the hash table, each of which >>>>is one ply closer to mate. There *can't* be a repitition, or it would be a >>>>different string. It is just like endgame tablebases, which do not need any >>>>history of positions. >>> >>> >>>I'm not sure I follow. Endgame tables have _all_ positions available during >>>their creation. That is how the algorithm works.. find a position that is >>>marked as "unknown" by backtracking from a position marked as "known". Then >>>you can mark the unknown entry as mate in one more move than the known entry. >>>But you must have _all_ positions stored during the creation... _every_ one. >> >>I thought that is what we were discussing. If you have a hash table large enough >>to store every position found in the search, then you do not need total path >>information with each position, which means you could solve chess by considering >>"only" about 10^25 positions. So, if Moore's law holds up, we could solve chess >>by the end of the century, rather than by the end of the universe. > > >First, how do you conclude 10^25? assuming alpha/beta and sqrt(N)? It is a classic alpha-beta search with a transposition table large enough to hold *all* positions found in the search. I'm guessing at the number of positions, but I feel that the same logic should hold, as only positions with one side playing perfectly would be seen.
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.