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Subject: Re: right now, at this very moment wac 141?

Author: Stuart Cracraft

Date: 15:20:32 09/30/04

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On September 30, 2004 at 04:53:48, Uri Blass wrote:

>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

Okay -- I'll try it.



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