Author: Will Singleton
Date: 19:38:30 01/19/99
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On January 16, 1999 at 23:19:04, Chris Moreton wrote: >Cutoffs in the full width triggers a history entry which adds a value which is 2 >to power Depth to the from-to array. When a history entry reaches a certain >value, all the values are halved. > Chris, Here's the results for my program on your HH question. Sorry it took so long, but I had to get a block of time to do it. Amateur 0.9g PVS Search - 7 ply Results are average nodes from a small test suite. No enhancements 23,000,000 HH only 9,000,000 TT only 6,700,000 HH + TT 3,000,000 HH + TT + killers 2,150,000 HH + TT + killers + caps 1,860,000 HH + TT + killers + caps + null 635,000 ------------------------------------------- all except HH 1,100,000 all except TT 1,700,000 So it appears that the HH is significant both by itself, and in combination with the others. This is PVS as opposed to plain AB, but I don't think that should make a lot of difference. The fact that you don't get a reduction when using HH by itself is troublesome. I would guess that you might have a bug somewhere. Try looking at the move list in the debugger for various positions, seeing if it looks reasonable. You also might try not storing HH values when depth <= 2. And using depth * 2 might be faster than 2 to the depth. Good luck. Will
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