Author: Robert Hyatt
Date: 07:17:40 01/20/99
Go up one level in this thread
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)...
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