Author: Robert Hyatt
Date: 18:00:39 05/05/01
Go up one level in this thread
On May 05, 2001 at 11:33:45, Uri Blass wrote: >On May 05, 2001 at 10:36:31, Robert Hyatt wrote: > >>On May 05, 2001 at 08:25:56, Uri Blass wrote: >> >>>There is a possibility to set selectivity of Deep Fritz to 0 and it means that >>>Fritz avoid null move pruning. >>> >>>The interesting question is how many effective plies are lost from null move >>>pruning. >>> >>>Some results suggest that not very much >>> >>>Tiger14(depth3)-Deep Fritz(selectivity=0,depth 3)35-15(6 draws) >>>Tiger14(depth4)-Deep Fritz(selectivity=0,depth 4) 31-19(8 draws) >>>Tiger14(depth 8)-Deep Fritz(selectivity=0,depth 8) 20-23(12 draws) is going to >>>be finished in an hour. >>> >>>The results without null pruning were not significantly better and at depth 3 it >>>is not clear if selectivity=0 is productive because tiger could win only >>>34.5-15.5 against selectivity=2. >>> >> >>Null-move gains at least 2 plies. But it loses some as well, as a 3 ply >>search with null move is not as good as a 3 ply search without... > >The results that I got do not give significant difference for Deep Fritz at >depth 3 but maybe I did not do enough games. > >The results clearly suggest that 5 or 8 plies without null move are better than >5 or 8 plies with null move. That makes perfect sense. Just watch the times. The null-move search will finish in seconds while it takes the non-null search minutes... > >Some new results for Fritz *without null move pruning* in the nunn2 match >The difference seems to be bigger when the depth is bigger > >Every match is 50 games > >Deep Fritz(depth 5)-Tiger14(depth 5) 25-25(14 draws) >Deep Fritz (depth 8)-Tiger14(Depth 8) 27.5-22.5(13 draws) > >Deep Fritz(depth 6) and Deep Fritz (depth 9) without null move did better >results against the same oponents so it seems that Fritz does not lose a full >ply even at depth 9 from pruning but again I did not do enough games. > >Uri I'm not sure it makes sense to compare null-move and non-null-move at the same depth. That is a _huge_ time handicap match...
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