Author: Christophe Theron
Date: 11:05:52 08/23/03
Go up one level in this thread
On August 23, 2003 at 04:37:57, Uri Blass wrote:
>On August 23, 2003 at 02:02:42, Christophe Theron wrote:
>
>>On August 22, 2003 at 16:31:24, Mike Byrne wrote:
>>
>>>On August 22, 2003 at 15:34:15, Christophe Theron wrote:
>>>
>>>>On August 22, 2003 at 10:17:13, Mihaly Szalai wrote:
>>>>
>>>>>[D]8/3p1P2/3Pp3/2p1P2K/p1p3P1/PpP3p1/1P3pP1/6k1 w - - 0 1
>>>>>
>>>>>White wins, but...
>>>>
>>>>
>>>>
>>>>I must be very tired, but I don't understand.
>>>>
>>>>Seems that the solution is 1.f8=R instead of 1.f8=Q
>>>>
>>>>But what is the difference between
>>>> 1.f8=R f1=Q 2.Rxf1 Kxf1
>>>>and
>>>> 1.f8=Q f1=Q 2.Qxf1 Kxf1 ???
>>>>
>>>>Explanations welcome (BTW Chess Tiger finds the solution after... some time, but
>>>>does not tell me why :)
>>>>
>>>>
>>>>
>>>> Christophe
>>>
>>>You are tired , it's not 1. f8Q f1Q , it's f8Q Kh2! and draw by stalemate will
>>>soon follow. So only f8R leads to victory.
>>
>>
>>
>>
>>Actually I'm not that tired.
>>
>>The real explanation is that I'm a lousy chess player!
>>
>>Thanks for taking the time to explain.
>>
>>
>>
>> Christophe
>
>If your engine can see f8R then you can also use it to tell you what happens
>after f8Q by playing f8Q and see that it plays Kh2.
>
>Another option is to ask it to tell you more information during the search.
>
>You can ask it not only to print the main line but every line of 2 plies that
>cause a cutoff.
>
>I think that it is also an important option for the user because if I give the
>computer hours to analyze I want to see not only the move that it likes but the
>reason that it decided not to play other moves.
>
>saving the full tree is impossible but saving all the moves that caused a cutoff
>some plies after the root position and showing them to the user is possible(some
>plies can be limited to 2 plies or 3 plies).
>
>Uri
You are right and actually it does not require to make big changes in the
engine.
The hash table has the information you need. Assuming you have more than a few
Kb of hash tables, the first 2 or 3 plies are almost entirely available, at
least the important refutations are kept there.
Christophe
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