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Subject: Re: Unusual Mate in 3

Author: Robert Hyatt

Date: 11:09:18 03/02/06

Go up one level in this thread


On March 02, 2006 at 12:02:16, Charles Roberson wrote:

>
>  But what happens when you step through the game???
>  I took insufficient material tests out of the interior nodes
>  and it found the mate in analysis mode.
>
>  BUT !!!!
>  When I then had it play both sides of the remaining plies,
>  it announced draw as soon as it (as black) took the queen with the bishop.
>
>  Sort of hate to see the mate then draw in move makeing.

This:

White(1): 1r5k/4NP1b/7K/8/6R1/8/8/8 w - - 0 1
White(1): move
              clearing hash tables
              time surplus   0.00  time limit 22.50 (+0.00) (3:30)
              depth   time  score   variation (1)
                1     0.00   4.60   1. Rg7
                1->   0.00   4.60   1. Rg7
                2     0.00   4.24   1. Rg7 Be4
                2     0.00     +1   1. Rg8+!!
                2     0.00     +3   1. Rg8+!!
                2     0.00     +M   1. Rg8+!!
                2     0.00  Mat03   1. Rg8+ Rxg8 2. fxg8=Q+ Bxg8 3. Ng6#
                2->   0.00  Mat03   1. Rg8+ Rxg8 2. fxg8=Q+ Bxg8 3. Ng6#
                3     0.00  Mat03   1. Rg8+ Rxg8 2. fxg8=Q+ Bxg8 3. Ng6#
                3->   0.00  Mat03   1. Rg8+ Rxg8 2. fxg8=Q+ Bxg8 3. Ng6#
                4     0.01  Mat03   1. Rg8+ Rxg8 2. fxg8=Q+ <EGTB>
                4->   0.03  Mat03   1. Rg8+ Rxg8 2. fxg8=Q+ <EGTB>
                5     0.04  Mat03   1. Rg8+ Rxg8 2. fxg8=Q+ <EGTB>
                5->   0.05  Mat03   1. Rg8+ Rxg8 2. fxg8=Q+ <EGTB>
              time=0.05  mat=1  n=3803  fh=98%  nps=1.00M
              ext-> chk=299 1rep=103 mate=2
              predicted=0  nodes=3803  evals=2261  50move=0
              endgame tablebase-> probes=11  hits=11
              SMP->  split=0  stop=0  data=0/64  elap=0.05

mate in 3 moves.


White(1): Rg8+
              time used:   0.05
Black(1): Rg8
Black(1): Rg8
              time used:   6.94
              time surplus  29.95  time limit 22.87 (+0.00) (3:33) [easy move]
              depth   time  score   variation (1)
                1     0.00   2.62   2. Nxg8
                1     0.00  Mat02   2. fxg8=Q+ <EGTB>
                1->   0.00  Mat02   2. fxg8=Q+ <EGTB>
                2     0.00  Mat02   2. fxg8=Q+ <EGTB>
                2->   0.01  Mat02   2. fxg8=Q+ <EGTB>
                3     0.01  Mat02   2. fxg8=Q+ <EGTB>
                3->   0.01  Mat02   2. fxg8=Q+ <EGTB>
                4     0.01  Mat02   2. fxg8=Q+ <EGTB>
                4->   0.01  Mat02   2. fxg8=Q+ <EGTB>
              time=0.01  mat=-4  n=166  fh=100%  nps=1.00M
              ext-> chk=12 1rep=0 mate=0
              predicted=0  nodes=166  evals=27  50move=0
              endgame tablebase-> probes=0  hits=0
              SMP->  split=0  stop=0  data=0/64  elap=0.01

mate in 2 moves.


White(2): fxg8=Q+
              time used:   0.01
Black(2): Bg8
              time used:  11.41
              time surplus  59.94  time limit 23.27 (+0.00) (3:37) [easy move]
              depth   time  score   variation (1)
                1     0.00   Mate   3. Ng6#
                1->   0.00   Mate   3. Ng6#
                2     0.01   Mate   3. Ng6# <EGTB>
                2->   0.01   Mate   3. Ng6# <EGTB>
                3     0.01   Mate   3. Ng6# <EGTB>
                3->   0.01   Mate   3. Ng6# <EGTB>
                4     0.01   Mate   3. Ng6# <EGTB>
                4->   0.01   Mate   3. Ng6# <EGTB>
              time=0.01  mat=0  n=6  fh=100%  nps=1.00M
              ext-> chk=4 1rep=0 mate=0
              predicted=0  nodes=6  evals=1  50move=0
              endgame tablebase-> probes=1  hits=1
              SMP->  split=0  stop=0  data=0/64  elap=0.01

White(3): Ng6#
1-0 {White mates}
              time used:   0.01


I only call something a draw if the search returns a draw score.  I then have
some code to discover why it is a draw (insufficient material, etc) but I don't
use that here at all...



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