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Subject: Re: Two mate position to solve.

Author: Larry Griffiths

Date: 10:24:25 09/06/00

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On September 06, 2000 at 11:15:05, leonid wrote:

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


I ran this using my program on a Pentium III 550Mhz Xeon.  I used a selective
extension that continues deeper if the king in in check on the current ply or
the previous ply.  (It only finds forced mates this way).


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

It looks like 9 PLYS to mate.  I have not fixed my PV to work with extensions
yet.

I tried the other position but was not able to find a mate.  I ran my program
for 3 hours this morning.

>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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