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Subject: Re: One mate to solve.

Author: leonid

Date: 18:18:47 07/20/01

Go up one level in this thread


On July 20, 2001 at 07:57:59, Heiner Marxen wrote:

>On July 19, 2001 at 09:39:46, Gian-Carlo Pascutto wrote:
>
>>On July 19, 2001 at 08:20:36, leonid wrote:
>>
>>>Hi!
>>>
>>>If you like, you can try this position:
>>>
>>>[D]rrqqqq1k/5q2/RRQQ1qqq/3Q3q/3QQQ1n/BQ3Q1n/BP3N1b/K4N1b w - -
>>>
>>>Please indicate your result.
>>
>>63.2 seconds on Athlon 1000
>>
>>Sjeng: prove
>>
>>Max time to search (s): 20000
>>
>>P: 0 D: 100000000 N: 3658466 S: 3658465 Mem: 153.52M Iters: 46218 MaxDepth: 29
>>Time : 63.240000
>>This position is WON.
>>PV: f4f6 g6f6 f3f6 h6f6 d5h5 f7h5 b3g8 f8g8 d4f6 d8f6 d6f6 g8g7 f6g7 h8g7 c6f6
>>
>>--
>>GCP
>
>In sharp contrast to the above result, the search for the shortest mate is
>much harder: after 10.2 hours (!) Chest says "No solution in 8 moves."
>
> depth   time    EBF[T]              EBF[N]  hash-speed
>#  1      0.00s                 0kN           0.87          1-         0
>#  2      0.00s                 0kN           1.00          1-         0
>#  3      0.16s                 8kN [ 95.32]  0.99        111-         0
>#  4      2.11s [ 13.19]       82kN [ 10.93]  1.25       5946-         0
>#  5     25.41s [ 12.04]     1008kN [ 12.25]  1.58      90608-         0
>#  6    253.41s [  9.97]    10394kN [ 10.31]  1.96     946154-         0
>#  7   2749.70s [ 10.85]   113463kN [ 10.92]  2.28    9993300-   1727617
>#  8  36553.28s [ 13.29]  1530367kN [ 13.49]  2.37  134410086- 125662185
>
>Since the EBF is above 13 and likely to increase for the next depth,
>I will not continue to go deeper with Chest.  :-(
>(Done on a K7/600 with 350 MB hash)
>
>Have a nice day,
>Heiner

Hi, Heiner!

Now I see only 9 move as not certain minimum number for this position. Mine
found mate by selective in 10 moves in 19 sec. Celeron 600. No hash.

I am not sure at what depth previous program found its mate. I tried to figure
out by counting the plys but had impression that 15 of them were indicated. If I
looked something in a wrong way and program found mate in 9, then this is the
mate in 9.

Brute force was perfect disaster for my program. Between 4 and 5 moves it was
almost 53. 5 moves search took already 26 min and 22 sec to say no. I stopped my
search right there. On this position my solver looked to me just like
"professional" one.

Cheers,
Leonid.



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