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Subject: How much rating do program lose from null move pruning at fixed depth?

Author: Uri Blass

Date: 05:25:56 05/05/01


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.

Fritz at depth d+1 at the default setting(selectivity=2) seems to be clearly
better than Fritz at depth d(selectivity=0) at small depthes.

I guess that at big depthes it changes but d=8 is not enough.

Uri



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