Author: Uri Blass
Date: 01:53:48 09/30/04
Go up one level in this thread
On September 29, 2004 at 19:58:54, Stuart Cracraft wrote: >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 I do not suggest to extend mate threats more than checks. Maybe you may limit it simply by not extending mate threats that are replies to check. Uri
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