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Subject: Re: One mate to solve...

Author: leonid

Date: 18:13:49 04/22/01

Go up one level in this thread

On April 22, 2001 at 19:32:11, Heiner Marxen wrote:

>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:
>>>>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
>>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.
>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.


In many "ordinary" positions my program will do just like your or slightly
higher in NPS. But when the number of pieces are considerable (positions that I
like for verification) then my NPS will be well often below number that you
said. Somewhere around 40k - 65k. This also was my finding that goes against all
"common sense". Very strange!!!

Selective search NPS will go usually between 2 and 10 times of brute force
search. This I never expected. Some bug?! Could be. Recently I found one in my
counting of NPS. Counting was done less, that it should do, just in one ply.
There only one position went to count instead of all positions that were used in
it. But fault there was not big.



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