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Subject: Re: One mate to solve...

Author: Heiner Marxen

Date: 16:32:11 04/22/01

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On April 22, 2001 at 18:19:17, leonid wrote:

>On April 22, 2001 at 17:36:18, Heiner Marxen wrote:
>
>>On April 22, 2001 at 09:57:10, leonid wrote:
>>
>>>Hi!
>>>
>>>If you want to solve one mate and say your result, then this is the position:
>>>
>>>[D]2R2bNn/Rp1n1k1b/1q1ppB1p/1Np1p1p1/2P1P2P/3P2PB/4Q2K/8 w - -
>>>
>>>If you program says nodes/per/second, please indicate it for this position.
>>
>>According to Chest this is a mate in 7 moves, with 3 solutions:
>>
>>Bxe6+ Kxe6 Qg4+  Kf7  Qxd7+ Kg6  Qf5+  Kf7  Nxh6+ Bxh6 Rxb7+ =*=  Nxd6#
>>Qh5+  Bg6  Bxe6+ Kxe6 Qg4+  Bf5  Qxf5+ Kf7  Qh7+  Bg7  Qxg7+ Ke6  Re8#
>>Rxf8+ Kxf8 Ra8+  Nb8  Rxb8+ Kf7  Qh5+  Bg6  Qxh6  Qd8  Nxd6+ Kxg8 Qxh8#
>>
>>On Athlon K7 600 MHz with 350MB hash: 950 seconds, 66,144 nodes/sec.
>>
>>Just for fun I tried this one also with hash table disabled.  Timings:
>>depth     with  without
>>#  3      0.02     0.02
>>#  4      0.42     0.42
>>#  5      5.23     6.90
>>#  6     62.19   113.11
>>#  7    950.10  2285.93
>>
>>Heiner
>
>Hi, Heiner!
>
>It is look like that we have, in general, very close NPS. With Rebel I could see
>that NPS goes somehow down with hash unable.
>
>Salut,
>Leonid.

Hello Leonid,

Yes, I would expect that NPS goes down with hash table enabled, since
maintaining the hash costs time, and does not reduce the work per node,
but rather saves complete nodes/subtrees.

For the above example without hash table my NPS increases to 73848.

Cheers,
Heiner



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