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Subject: Re: Try solve this mate.

Author: Heiner Marxen

Date: 14:27:51 10/21/01

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On October 21, 2001 at 13:03:27, Paul wrote:

>On October 21, 2001 at 01:43:54, leonid wrote:
>
>>[D]4r3/1KPQrNBR/1PQ1b1QR/1QQBbQQN/3n1n2/2q3q1/1qq3qq/1q5k w - -
>>
>>Please indicate your result.
>>
>>Thanks,
>>Leonid.
>
>Hi Leonid,
>
>Pretz finds a mate in 11 reasonably quick, but it takes a long time on different
>settings to lower that to a mate in 10 ... will have to conjure up something to
>speed that up:
>
>01:01 WM11 12 Nxg3+ Kg1 Ne2+ Qxe2 Qxb1+ Qce1 Qxg2+ Nxg2 Rxh2 Rb8+ cxb8=Q Rxd7+
>Qxd7 Bxd5+ Qdxd5 Qexb1 Qcxd4+ Bxd4 Rh1+ Kf2 Qgg3#
>
>09:36 WM10 10 Nxg3+ Kg1 Rxh2 Rb8+ Kxb8 Bxc7+ Qcxc7 Re8+ Qxe8 Qcf3 Bxd4+ Qxd4
>Qxd4+ Qe3 Rxg2+ Qxg2 Qxe3+ Qf2 Qbxb1#
>
>Groetjes,
>Paul

Hi Leonid, Hi Paul,

Chest on my K7/600 (350 MB hash) used already nearly 9000 seconds (2.5 hours)
to proove "no mate in 9", so may be Pretz does not so bad, really.
Also, the search for Chest does appear to be somewhat unstable:

#  1      0.00s                 0kN           0.87          1-         0
#  2      0.00s                 0kN           1.00          1-         0
#  3      0.01s                 1kN [ 12.12]  0.95         68-         0
#  4      0.16s [ 16.00]        7kN [  8.32]  1.04        701-         0
#  5      1.05s [  6.56]       53kN [  7.99]  1.18       4912-         0
#  6     23.45s [ 22.33]     1150kN [ 21.65]  1.50     139214-         0
#  7    175.82s [  7.50]     8700kN [  7.56]  1.93    1111052-         0
#  8   1181.87s [  6.72]    58998kN [  6.78]  2.32    7380574-    367907
#  9   8966.72s [  7.59]   445492kN [  7.55]  2.67   54287666-  45539765

That spike at depth=6 is quite uncommon.  That the EBF at the last iteration
increased (most of the time it decreases), is most probably due to the fact
that the mate is near.  Currently Chest searches depth=10, but that will take
around a day.  More to come...

Cheers,
Heiner



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