Author: Ulrich Tuerke
Date: 13:50:40 12/22/04
Go up one level in this thread
On December 22, 2004 at 16:27:13, Uri Blass wrote: >On December 22, 2004 at 16:19:05, Ulrich Tuerke wrote: > >>On December 21, 2004 at 05:11:13, Uri Blass wrote: >> >>>On December 21, 2004 at 03:53:49, Joachim Rang wrote: >>> >>>>On December 20, 2004 at 16:32:24, Jouni Uski wrote: >>>> >>>>>Shredder 8 reaches quite stunning averaga search dept. E.g. with only 15 >>>>>second/move average with Pentium 2400 and 128MB hash it averages 15,2 ply! For >>>>>comparison Fritz Bilbao and Gandalf 6 reach both same 12,7 ply. No wonder >>>>>Shredder beats them 13 - 7 and 14 - 6. Of course 2,5 ply is a lot difference! >>>>>Is there any amateur or pro engine, which can equal Shredder in depth - Junior's >>>>>half plys can be forgotten. >>>>> >>>>>Jouni >>>> >>>>Here is a 1-minute search on my Athlon XP@1540 MHz, with Shredder 7.04 default >>>>and Fruit X with aggressive delta, futility and history pruning. Both engines >>>>were analysing together under Arena. Compare the depth! >>> >>>I am surprised to read that fruit2 has history pruning. >>>I understood that Fabien does not plan to implement history based pruning and >>>here is the source of my misunderstanding: >>> >>> >>>The reason is the following link: >>>http://f11.parsimony.net/forum16635/messages/68164.htm >>> >>>Fabien claimed in that link: >>> >>>"Forward pruning in the main search is a separate topic that I don't intend to >>>address now. If I ever do, I expect it will require years of work (same for a >>>proper move ordering)." >>> >>>Note that I consider history based pruning as forward pruning in the main >>>search. >> >>Doesn't the history heuristic simply mean that moves which had often produced >>cuts in the previous iteration will be tried as killers ? > >No > >It means reducing depth of moves that almost always caused fail low based on >statistics. Hm ..., with the intention to avoid production of these nasty fail lows again by reducing their search depth ? On 1st view, this idea seems very risky and poorly motivated to me. Anyway thanks for your remark, Uri; in this case this technique should be classified as "forward pruning". Seems that I have missed a lot here. Uli > >Uri
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