Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: The Null Move Killer

Author: Robert Hyatt

Date: 17:02:34 09/30/04

Go up one level in this thread


On September 30, 2004 at 18:23:20, Stuart Cracraft wrote:

>On September 30, 2004 at 18:07:46, Robert Hyatt wrote:
>
>>On September 30, 2004 at 15:50:43, Stuart Cracraft wrote:
>>
>>>On September 30, 2004 at 09:38:04, Robert Hyatt wrote:
>>>
>>>>On September 30, 2004 at 00:52:04, Will Singleton wrote:
>>>>
>>>>>On September 29, 2004 at 23:52:15, Stuart Cracraft wrote:
>>>>>
>>>>>>[D] 4r1k1/p1qr1p2/2pb1Bp1/1p5p/3P1n1R/1B3P2/PP3PK1/2Q4R w - - bm Qxf4;
>>>>>>
>>>>>>In this position I had everything turned on and got the solution
>>>>>>in a little more than 1 1/2 minutes:
>>>>>>
>>>>>> 1/11  g2f1  0.01 -953      945 g2f1 f4d5
>>>>>>                                g2f1 f4d5
>>>>>> 2/12  g2f1  0.01 -953     1644
>>>>>>                                g2f1 f4d5 c1g5
>>>>>> 3/12  g2f1  0.02 -953     5064
>>>>>>                                g2f1 f4d5 c1g5 d5f6
>>>>>> 4/20  g2f1  0.09 -953    20655
>>>>>>                                g2f1 f4d5 b3d5 c6d5 c1c7 d6c7 f1g1
>>>>>> 5/22  g2f1  0.65 -953   168943
>>>>>>                                g2f1 b5b4 b3a4 f4d5 f6g5 d5e7
>>>>>> 6/26  g2f1  2.59 -953   620310
>>>>>>                                g2f1 b5b4 mtmt
>>>>>> 7/32> g2f1 60.58 -552 14192153 g2f1 e8c8 c1b1 f4d5 b1e4 d6b4 f6e5 c7b6
>>>>>>                                g2f1 e8c8 c1b1 f4d5 b1e4 d6b4
>>>>>> 7/34  c1f4 99.42 5113 24537823 c1f4 e8e6 f4g5 d7e7 b3e6 e7e6 h1d1 d6e7 f6e7
>>>>>>                                c1f4 e8e6 f4g5 d7e7 b3e6 e7e6 h1d1
>>>>>>
>>>>>>
>>>>>>I turned off null move (R=2) and got the solution in about 11 seconds:
>>>>>>
>>>>>>Alpha=-1332 Beta=-531 Maxdepth=9999999 MaxTime=99999999
>>>>>> 1/11 g2f1  0.01 -953      908 g2f1 f4d5
>>>>>>                                g2f1 f4d5
>>>>>> 2/12 g2f1  0.01 -953     1565
>>>>>>                                g2f1 f4d5 c1g5
>>>>>> 3/14 g2f1  0.07 -953    20084
>>>>>>                                g2f1 f4d5 c1g5 d5f6
>>>>>> 4/22 g2f1  0.60 -953   131543
>>>>>>                                g2f1 f4d5 b3d5 c6d5 c1c7 d6c7 f1g1
>>>>>> 5/26>g2f1  6.80 -552  1607444
>>>>>>                                g2f1 b5b4 b3a4 f4d5 f6g5 d5e7
>>>>>> 5/36 c1f4 10.70 2260  2466497 c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 d7d6
>>>>>>
>>>>>>                                c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 d7d
>>>>>>
>>>>>>So now my question is, would it make sense to consider an idea of
>>>>>>disabling null move under additional circumstances if those
>>>>>>circumstances can be identified.
>>>>>>
>>>>>>   endgame
>>>>>>   side to move in check
>>>>>>   inside principal variation
>>>>>>   last move a null move
>>>>>>
>>>>>>These are the ones I disable for -- I don't disable null move for
>>>>>>any material-related or alpha/beta related measures but perhaps
>>>>>>I should. Are any in common use?
>>>>>>
>>>>>>Stuart
>>>>>
>>>>>If the previous move was a piece moving near the enemy king, I don't null move.
>>>>>Also, don't null near the leafs.
>>>>
>>>>
>>>>That is a bad idea.  That is where most of the _gain_ from null-move happens.  I
>>>>do it everywhere without this WAC141 problem stuff bothering anything.
>>>
>>>Do you mean for both near the leafs and enemy king or only one or the other?
>>
>>
>>Near the leaves...
>>
>>Actually near the frontier as frontier nodes are those along the outer bound of
>>the basic search.  Leaves (in my program) never have null moves anywhere since
>>they are in the q-search...
>
>Okay now I'm really confused.
>
>Frontier = depth = 0
>Pre-frontier = depth = 1
>Pre-Pre-frontier = depth = 2
>Leaf = terminal node after quiescence search (no more caps, etc.) possible

Yes...


>
>Is that how you're classifying it? So no null move at depth = 1 is bad.


yes again...


>
>Currently my program excludes null move if depth <= 1 (i.e. frontier
>or pre-frontier in the above terminology). I have no idea if the above
>terminology is generally accepted or not and am curious what others
>use.
>
>Stuart



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.