Author: Robert Hyatt
Date: 19:23:53 07/20/02
Go up one level in this thread
On July 20, 2002 at 09:20:41, Uri Blass wrote: >On July 20, 2002 at 08:38:52, Sune Fischer wrote: > >>On July 20, 2002 at 08:13:44, Gian-Carlo Pascutto wrote: >> >>>On July 20, 2002 at 08:04:01, Sune Fischer wrote: >>> >>>>I think it matters "a factor of 2". >>>> >>>>1) it helps you to prune >>>>2) you get better evaluation in the upper plies when you can return a score >>>>based on a deeper search. >>>> >>>>number one will show itself directly because you iterate deeper, the second one >>>>you don't "see", but it does improve depth along some branches in the same way. >>> >>>1) I get +- 10% hash hits (and less prunes) in typical middlegame. Not enough to >>>matter a factor of two (but I didnt check this so not 100% sure). >>> >>>2) Uh? >> >>You have 1 ply to go, you probe and get a hit based on a 10 ply search. >> >>Or, what is perhaps more likely, a 6 ply result when you only had 4 plies to go, >>that is still 2 more plies of accuracy and you also prune/transpose at the same >>time. > >I doubt about the accuracy. > >You may remember a draw score and use it >when practically it is not a draw because >the draw score is based on previous positions and when >you get the same position again the previous positions >are not the same. > >Uri Simple test, again. Use fine 70. No hashing will take you 26 plies to find the winning move Kb1, with the score showing you win a pawn. With a decent hash table, you will solve this somewhat shallower. Crafty finds this at depth=18 for example. It gets a 26 ply result from a 18 ply search due to the effect Sune mentioned...
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