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Subject: Re: Crafty Node Count Question

Author: Uri Blass

Date: 19:20:14 11/12/04

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On November 12, 2004 at 22:04:34, Mike Byrne wrote:

>sel 0 0 , ext set to 0
>
>sd=1
>
>Black(1): new
>White(1): g
>              time surplus   0.00  time limit 22.50 (3:30)
>              depth   time  score   variation (1)
>                1     0.00   0.16   1. Nf3
>                1->   0.01   0.16   1. Nf3
>              time=0.01  cpu=0%  mat=0  n=60  fh=100%  nps=10K
>              ext-> chk=0 cap=0 pp=0 1rep=0 mate=0
>              predicted=0  nodes=60  evals=20  50move=0
>              endgame tablebase-> probes=0  hits=0
>              SMP->  split=0  stop=0  data=0/128  cpu=0.00  elap=0.01
>
>White(1): Nf3
>              time used:   0.01
>
>-> why 60 nodes here?
>
>( thought it would be 20)

I can only guess that maybe the same node is searched again with different
window.

>
>same settings, sd=2
>
>Black(1): new
>White(1): sd 2
>search depth set to 2.
>White(1): g
>              time surplus   0.00  time limit 22.50 (3:30)
>              depth   time  score   variation (1)
>                1     0.00   0.16   1. Nf3
>                1->   0.02   0.16   1. Nf3
>                2     0.02  -0.14   1. Nf3 Nc6
>                2->   0.02  -0.14   1. Nf3 Nc6
>              time=0.02  cpu=0%  mat=0  n=119  fh=100%  nps=10K
>              ext-> chk=0 cap=0 pp=0 1rep=0 mate=0
>              predicted=0  nodes=119  evals=59  50move=0
>              endgame tablebase-> probes=0  hits=0
>              SMP->  split=0  stop=0  data=0/128  cpu=0.00  elap=0.02
>
>White(1): Nf3
>              time used:   0.02
>Black(1):
>
>-> why 119 nodes here
>
>I thought it would be 400.

No reason for 400
alphabeta with no pruning and extensions means that you save time by not
searching illogical lines and after finding that 1.Nf3 is 0.14 pawns for black
and finding that 1.a3 e5 is 0.20 pawns for black you save time by not searching
1.a3 d5 because 1.a3 is not better for white than 0.2 pawns for black and
finding it's exact score is waste of time.

Uri



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