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Subject: Re: Two mate position to solve.

Author: leonid

Date: 08:15:05 09/06/00

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On September 06, 2000 at 08:46:01, Larry Griffiths wrote:

>On September 06, 2000 at 07:34:48, leonid wrote:
>
>>Hello!
>>
>>Please, solve this position and say how much difference your hash table did.
>>
>>Indicate any parameter of your search that you consider important.
>>
>>It is pretty normal position from the book.
>>
>> kb6/B3P3/K1P5/p7/P7/3r4//8/8 w
>
>Here is what I got for this position...
>
>HashTable is 8 meg.
>
>Extracted bm=
>
>00:00:00.031  2 -           -3000   Bxb8 Kxb8  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?
>00:00:00.046  2 -            5000   e8   Rd1   ?  ?  ?  ?  ?  ?  ?  ?  ?  ?
>00:00:00.046  2 -            5000   e8    <----------
>
>00:00:00.109  3 -            8000   Bxb8 Rd1  e8   Kc7  Qxd8  ? cxd7 Kc7  Qg8
>?  ?  ?  ?
>00:00:00.109  3 -            8000   Bxb8  <----------
>
>00:00:00.171  4 -           -1000   Bxb8 Re3  e8   Rxe8 Bxe5  ? Qf5  Rxb3 Qxd3
>Kxc6  ?  ?  ?  ?
>00:00:00.187  4 -            5000   e8   Rb3  Bxb8 Rxb8 Qxc6 Kxb8 Qb7   ? Qa7
>?  ?  ?  ?  ?
>00:00:00.203  4 -            5000   e8    <----------
>
>00:00:00.312  5 -            2000   Bxb8 Re3  Bd6  Re6  e8   Rxe8 e8   Rxe8 Kb4
>Rxc7 Nxc3  ?  ?
>?  ?
>00:00:00.406  5 -        77777771   e8   Rb3  c7   Rb6  Bxb6  ? Qxb3 Rxb7 e8
>Kd7  Qxd6  ?  ?
>?  ?
>00:00:00.437  5 -        77777771   e8    <----------
>
>00:00:00.531  6 -               0   Bxb8 Re3  Kxa5 Kxb8 c7   Kc8  e8   Rxe8 e8
>Rxc8 axb5  ?  ?
>?  ?  ?
>00:00:00.750  6 -        77777771   e8   Rb3  c7   Rb6  Bxb6  ? Qxb8  ? axb5  ?
>Bxg3  ?  ?  ?  ?
>?
>00:00:00.812  6 -        77777771   e8    <----------
>
>00:00:01.234  7 -            3000   Bxb8 Re3  Bd6  Re6  Kxa5 Re1  e8   Kxb8 cxd8
> ? Kb4  Kxc7
>Kxa6  ?  ?  ?  ?
>00:00:02.390  7 -        88879990   e8   Rb3  Qd7  Bc7  Qc8  Bb8  Qb7  Rxb7 cxb7
> ?  ? Rxa4 Qb7
>?  ?  ?  ?
>00:00:02.531  7 -        88879990   e8    <----------
>
>
>Elapsed Time= 2.53 seconds

Excellent time! But on what computer and with what program you solved this
position? What kind of search was executed? Selective or brute force?

And in how many moves your program solved? I have the impression that in 7, but
maybe it is my mistake.

Leonid.



>>
>>My solver could not resolve it by selective search and went paintful 24 sec (AMD
>>400) before finding the mate. Mine have no hash tables. When I went to see it on
>>Rebel 10, I was impressed. His time in solving the position knew around 6 fold
>>improvement between solution without hash and with it. His hash was 28 M.
>>
>> q1bkb1q1/2nqn3/1BrnrB2/1R1Q1R2/1NNQNN2/2Q1Q3/2QQQ3/3K4 w
>>
>>This last, is the fantasy position. Did it yesterday. Also could not solve it at
>>minimum number of moves by selective search. It took lengthy 18.5 min to reach
>>minimum number of moves for mate by brute force. Selective search can reach it
>>only if one move more is permitted. Then it take it in 2 sec. But how much hash
>>table could help in this position?
>>
>>Thanks,
>>Leonid.



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