Author: Peter Kappler
Date: 22:06:11 08/16/00
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On August 16, 2000 at 23:09:02, Christophe Theron wrote: >On August 16, 2000 at 19:47:27, Dan Andersson wrote: > >>On August 16, 2000 at 19:34:21, Gian-Carlo Pascutto wrote: >> >>>On August 16, 2000 at 18:52:03, David Rasmussen wrote: >>> >>>>My Qsearch usually takes up 70-80 % of the nodes searched. >>>>What are the, say, 10 best ideas/techniques to cut this number down? >>> >>>a) don't qsearch >>> >>>b) use futility pruning >>> >>>c) use SEE futility pruning >>> >>>d) live with it...qsearch % tends to be high in every chessprogram >>> >>>>P.S. I am writing a new chess program from scratch and I'm very much in love >>>>with the scientific beauty of MTD(f). What are the pratical pros and cons of >>>>doing MTD(f). What are the pitfalls etc. ? >>> >>>It causes trouble with search trics that depend on alpha/beta values. >>But introduces new tricks. Especially if one uses ETC. > > >Sorry to ask (actually you certainly expect someone will ask), but > >What is ETC? > > > Christophe > Enhanced Transposition Cutoffs. If the current position isn't in the hashtable, you try each legal move in the hope that one of them will produce a hash hit with a score that can cause a cutoff. I think Schaeffer(?) wrote a paper on this... --Peter > > >>>Its harder to get a PV. >>Yep. >>>It's not necessarily faster than PVS. >>In the best case MTD and PVS will search the same nodes. And if you use ETC I'm >>almost certain it will search a smaller tree in the average case. ETC will slow >>search down, but there are ways to alleviate that. F.ex no ETC the last N plies. >>>Depends more on large hashtables than other methods. >>Í would say that it suffers badly from to small TTs instead, maybe even >>benefitting more from large TTs than other methods. (Thats pure speculation) >>> >>>>P.P.S. Why is my chess program code so messy? >>> >>>Because its a chessprogram. >>> >>>-- >>>GCP >> >>Regards Dan Andersson
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