Author: Eric Oldre
Date: 21:16:36 07/21/04
Go up one level in this thread
On July 21, 2004 at 23:13:26, Robert Hyatt wrote: >On July 21, 2004 at 23:03:59, Eric Oldre wrote: > >>On July 21, 2004 at 22:09:58, Robert Hyatt wrote: >> >>>On July 21, 2004 at 16:55:07, Eric Oldre wrote: >>> >>>>lets say you are searching a position with iterative deepening. >>>>at depths 3,4,5 it finds a best move of Qd3. then at depth 6 >>>>the best move changes to c4. >>>> >>>>When you start searching to depth 7, you clearly would want the >>>>first move you search to be c4, and this shouldn't be a problem >>>>if your transposition tables are working right. Since the best >>>>move should be stored in it. >>>> >>>>however, a good move to try 2nd would be Qd3, but your transposition >>>>tables aren't going to let you know that, at least not in the implementations >>>>that I have normally heard about. >>>> >>>>I was thinking that one way to overcome this would be to keep 2 "best" moves >>>>in the trans table. one to try first, and one that was a best move, before >>>>being replaced by a deeper search. >>>> >>>>Are other people doing this? or have you discovered that the cost is greater >>>>than the benefit? >>>> >>>>Eric >>> >>> >>>Nobody uses the transposition table to order the moves at ply=1. >> >>Well not quite, I do! > >You only have _one_ position at the root of the search. How many moves can you >store in one position? :) > >More than one is a huge waste since "best" is all that counts in alpha/beta... i think that you might have misunderstood what i was trying to say, or i misunderstood you... I meant i get the first move to search from the trans table. and then use SEE after that. >>Of course i hope to get that replaced in the future with something better. :) >> >> >>> Much easier is >>>to just generate the ply=1 move list before you start the search, and as you >>>find a new best move, move it to the top of the list, pushing others down 1 >>>slot. This makes you search the best move from the previous iteration first, >>>then the next-best move from the previous iteration second, etc...
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