Author: Stuart Cracraft
Date: 09:25:41 09/23/04
Go up one level in this thread
On September 22, 2004 at 22:17:10, Stuart Cracraft wrote: >On September 22, 2004 at 21:09:33, Robert Hyatt wrote: > >>On September 22, 2004 at 20:55:37, Stuart Cracraft wrote: >> >>>On September 22, 2004 at 19:38:53, Robert Hyatt wrote: >>> >>>>On September 22, 2004 at 18:53:51, Stuart Cracraft wrote: >>>> >>>>>Are you saying I should consider marking each move after its search, then >>>>>back up the score value, node count, etc., then resort based on that? >>>>> >>>>>I could see that various parts of the subtree have generated new history >>>>>heuristic scores for from/to move coordinate pairs and that a resort could >>>>>affect the remaining move order. >>>>> >>>>>I don't currently resort at any level after the movegen at that level. >>>>>I just search all the moves in the original post-movegen-sort-order. >>>>> >>>>>I am fine with considering doing continual resorts but worry about the >>>>>overhead and the return. But with it being the all important move-ordering, >>>>>what have you seen in doing these resorts in terms of improvement >>>>> >>>>>Stuart >>>> >>>>There is _no_ overhead. It is done only at the root, once per iteration. For a >>>>12 ply search, a total of 12 times. That won't use measurable CPU time. The >>>>point is that root move ordering is critical for efficiency.. >>> >>>That's a new one on me. I always thought it was throughout the tree. I'll >>>have to chew up some code on this one. >> >> >>Ordering is important everywhere. But this thread was about ordering at the >>_root_ of the tree... > >I will try it. Please see earlier post -- result for ply == 0 reordering based on history heuristic is +2 on problems and -2% on search tree. This is not a bad result and certainly better than most things I try. I don't quite follow how total nodes searched can be used to resort the movelist -- you've already searched those moves. What use are they for a resort? There's no flow-over effect to the unsearched moves. Stuart
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