Author: Paul
Date: 13:05:36 04/02/01
Go up one level in this thread
On April 02, 2001 at 15:30:15, Dann Corbit wrote: >On March 30, 2001 at 14:49:09, Christophe Theron wrote: >[snip] >>I'm also using this condition (capture && nbpiece<=5) and I guarantee I get the >>hard disk working real hard in endgames positions. >> >>The result on endgame test suites was a real disaster with this condition only. >>So I added a condition not to probe when too close (and beyond) from the >>horizon. >> >>Then I also added hand crafted endgame knowledge to decide in which cases a >>probe is useless. >> >>The result is that Tiger is hardly slower (in NPS) in the endgame, but still >>benefits from TBs. > >What about shifting caches sizes in endgame? > >E.g. suppose you have 256 megs for cache/hash/whatever. > >If you have only one or two pawns left, you don't need a giant pawn hash. >Instead of searching 16 plies deep innacurately, it might be a lot better to >reorganize the cache/hash strategy, and give a very large tablebase cache. If >you only have seven total chessmen on the board (for instance) I suspect you >will mostly be hitting the same tablebase files over and over. So if you make a >large cache for them (or perhaps even memory map them completely) it might mean >a big speedup for endgame searching. > >Seems like it might be worth an experiement anyway. > >Try some different curves as a function of how sparse the board is and what is >on it. > >Make a table with fields something like this: > >| Total Chessmen | Total Pawns | Hash | Pawn Hash | EGTB Cache (4) | EGTB Cache >(5)| > >Table entries are the outcomes of the searches. > >And then run an experiment and see how it turns out. > >Maybe you have already done so. But I don't think you can change tb cache size "on the fly", if that's what you're intentions are. You have to reinit the tables after that, and that takes a long time. So it isn't possible during game play. But maybe I'm mistaken ... Paul
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