Author: Will Singleton
Date: 08:47:38 01/20/99
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On January 20, 1999 at 10:17:40, Robert Hyatt wrote: >On January 19, 1999 at 22:38:30, Will Singleton wrote: > >>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 > > >Just a note that using _all_ of those should not continuously drop your >node count. Remember that at some nodes we search _all_ moves and ordering >is worthless there. And at other nodes we want to fail high after 1 move. > >I added killers, not because they made the tree smaller (since they are just >a special case of history) but because I can try those two non-capture moves >before generating any non-capture moves (which saves time, not nodes). > >I would suspect that you may still have some move ordering issues to clean up >based on your numbers, because I can take out either history or killer and >my node count doesn't shoot way up (unless I remove both)... Bob, Yes, I'm sure I have some ordering issues to work out. It's actually a miracle it works at all. And the above numbers were from a small sample. I use killers a little differently than others. I try them after good caps, and maintain a list of 4 best. So it's rather more like a mini-HH than killers. Will
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