Author: Uri Blass
Date: 08:33:45 05/05/01
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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. 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
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