Author: Stuart Cracraft
Date: 22:15:11 09/29/04
Go up one level in this thread
On September 30, 2004 at 00:46:26, Uri Blass 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
>
>It is better to disable your recapture extensions.
Not completely but heavily limited now to require ply<=iply+1.
>The problem here is not null move pruning and null move pruning willnot change
>the depth that you solve the problem when you will implement correctly checks in
>the qsearch.
I knew you'd say that. :-)
I do check evasions in the quiescence.
>
>The target of chess programs is not to solve 141 faster but to play better.
>I am almost sure that if only the recapture extension save you many plies in 141
>then you implement it in a way that is counter productive for games.
You state the obvious about chess but have you stopped to think that
some people have different goals than simply playing better or that
their goals can change from one to another through the years?
>
>
>I wonder how do you get depth 5 without null move pruning
I do too! Even with limiting recaptures drastically it still is
good. I think there are some hidden extensions I stumbled across
that are excessive but helpful. Clearly, limiting recapture extension
from unlimited to heavily limited (1 beyond iteration depth at
the current ply) *improved* solution rate for WAC 141 with and
without null move drastically.
>
>Can you post the remaining depth after every move in the line
>1.Qxf4 Bxf4 2.Rxh5 gxh5 3.Rxh5 Bh6 4.Rxh6 Rd6 Rh8#
I wouldn't know how to start with this.
>
>There are no checks in this line except the mate and you do checks in the
>qsearch so without recapture extensions you need at least 9 plies for it(after 8
>plies you enter qsearch after Rd6 and do not find the move Rh8 mate.
>
>If recapture extensions lead to 4 plies extension then it seems clear that your
>new program will be clearly weaker in games.
They were too much.
>
>I suspect that you extend 4 plies in this line because you extend 1 ply every
>time that the last 2 moves are captures.
1 ply for every recapture as long as not already extended at this ply.
But now limited to only one recapture as long as the current ply is
<=iteration_ply+1.
>
>It is clearly a bad idea to do it and it is clear that even with more reasonable
>restriction of the recapture extension it is not productive for a lot of
>programs.
I agree with you.
>
>I suggest that you test the version with the recapture extension in games
>against the version without the recapture extension if you do not believe me
>that your recapture extension is a bad idea.
Self-testing is beyond where I am now.
>
>
>Uri
I have limited the recapture extension to 1 beyond the iteration depth.
Without the null move, this cuts solution time for WAC #141 from <11 to
6.16 seconds. With the null move, it cut the solution time for WAC #141
from 95 to 67 seconds, a 30% improvement:
Alpha=-1332 Beta=-531 Maxdepth=9999999 MaxTime=999999999
1/ 9 g2f1 0.00 -953 511 g2f1 f4d5
g2f1 f4d5
2/ 9 g2f1 0.01 -953 884
g2f1 f4d5 c1g5
3/10 g2f1 0.02 -953 3503
g2f1 f4d5 c1g5 d5f6
4/13 g2f1 0.07 -953 13396
g2f1 f4d5 b3d5 c6d5 f1g2 d6e7
5/17 g2f1 0.56 -953 126695
g2f1 b5b4 b3a4 f4d5 f6g5 d5e7
6/22 g2f1 2.13 -953 392199
g2f1 b5b4 mtmt
7/27> g2f1 37.43 -552 8352497 g2f1 e8c8 f6g5 f4e6 b3e6 f7e6 c1c2 d7g7 f1g1
g2f1 e8c8 f6g5 f4e6 b3e6
7/28 c1f4 67.77 5113 15822500 c1f4 e8e6 f4g5 d7e7 b3e6 e7e6 h4e4 e6e4 f3e4
c1f4 e8e6 f4g5 d7e7 b3e6 e7e6 h4e4 e6e4 f3e4
8/28 c1f4 77.97 5113 17753858
c1f4 e8e6 f4g5 d7e7 b3e6 e7e6 h4e4 e6e4 f3e4
9/30> c1f4 129.07 5513 29621880
c1f4 e8e6 f4g5 d7e7 b3e6 e7e6 h4e4 e6e4 f3e4 mtm
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