Author: Stuart Cracraft
Date: 16:58:54 09/29/04
Go up one level in this thread
On September 29, 2004 at 19:54:50, Stuart Cracraft wrote: >On September 29, 2004 at 18:34:40, Uri Blass wrote: > >>On September 29, 2004 at 18:20:45, martin fierz wrote: >> >>>On September 29, 2004 at 16:21:43, Uri Blass wrote: >>> >>> >>>>I think that it is clear that extending every nate threat by a full ply will >>>>blow your search. >>>> >>>>If you do not use partial extensions then I suggest that you do not extend mate >>>>threats unless you have some conditions to extend them only near the root and >>>>not every where. >>>> >>>>Uri >>> >>>i extend mate threat by a full ply always. and my search isn't blowing up, at >>>least not that i notice. then again, WAC 141 shows some strange behavior with my >>>latest version: >>> >>>MUSE 0.89.10 UCI 30 MB: >>> >>> 1 00:00 -1.65 Kg2g1 >>> 2+ 00:00 -2.36 Kg2f1 >>> 2 00:00 -2.36 Kg2f1 Nf4d3 >>> 3 00:00 -1.22 Kg2f1 Re8b8 Kf1e1 >>> 4 00:00 -2.13 Kg2f1 Kg8h7 Bb3d1 Nf4d3 >>> 5 00:00 -2.16 Kg2f1 Re8e2 Kf1g1 Nf4d5 Kg1f1 >>> 6+ 00:00 -1.66 Qc1xf4 >>> 6 01:24 M6 Qc1xf4 Bd6xf4 Rh4xh5 g6xh5 Rh1xh5 Bf4h6 Rh5xh6 >>> >>>it sees Qxf4 after 0 seconds (this is on a slowly 1.4GHz P4), but needs a very >>>long time to resolve it. but at least it sees Qxf4 in 0 seconds :-) >>> >>>cheers >>> martin >> >>If you extend also checks by a full ply then there are cases when there is a >>long sequence >>check ,escape threat mate,check,escape threat mate and it means that you may >>have big problems to search deep in position when one side threats mate but the >>opponenthas a lot of checks because he tries to do perpetual checks. >> >>You can easily search some lines to more than 100 plies at small depth and I do >>not believe that it is a good idea. >> >>Uri >> >> >>Uri > >This is very useful. Okay, in main search I can just start off with >revaluing check extension to 0.75 instead of 1 but I'd expect that >since I have few extensions, very few checks would be searched. >How would you handle reducing check extension value in such an >arrangement. > >Also, my quiescence search always investigates all check evasions >to any depth. Should I be doing that? > >Stuart The only thing I can think of is to keep an Extensions[Ply] and see, at ply, if Extensions[Ply-1]+Extensions[Ply], is > 1 and if so then to extend, unless Extensions[Ply-1]>1 in which case only extend if Extensions[Ply]>1 also. Then also to start with check extension revalued to 0.75. But since I can't visualize whether this would work for the tree, I haven't tried. I need to just plug it in and see what happens. Stuart
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