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Subject: Re: How to manage extensions?

Author: Jan Pernicka

Date: 04:10:40 03/28/00

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On March 22, 2000 at 10:10:51, Inmann Werner wrote:

>On March 22, 2000 at 09:54:23, Jan Pernicka wrote:
>
>>On March 22, 2000 at 08:32:37, Inmann Werner wrote:
>>
>>>On March 22, 2000 at 08:05:13, Jan Pernicka wrote:
>>>
>>>>On March 22, 2000 at 07:12:59, Inmann Werner wrote:
>>>>
>>>>>On March 22, 2000 at 06:30:58, Jan Pernicka wrote:
>>>>>
>>>
>>       So - what's maximum searching depth of your program (say, in middle
>>        game) ?
>
>about 12 plys in normal timed games...(>1 min per move)
>

  I suppose you enjoy bitboards.... :)
  I'd like to know how much faster is it comparing with "classic" board...

>>>- null move extension, i only allow once in a branch (it blows up the tree too
>>>much)
>>
>>    - this surprised me - I think that null move ext. shout shorten the time
>>      of search. (In other words - you have experienced that null-move ext.
>>      fails too often - and thus regular research has to be done?)
>>
>dont mix things. Null move shortens the tree a lot. But if the null move brings
>back the information, that i get mated, if i do the null move, that leads to a
>null move extension. The normal nullmove condition cuts the tree!
>

  Thank you for explanation, but - it would be, I think, better, to extent
  only on "mate in 1" threat and not to all mate thrats (in some sharp games
  it seems very reasonable... - or not?).


>I extend up to 9 times in one branch, but only once at one ply in this branch.
>I extend, but one ply deeper, if I come there and have no cutoff before. If I
                                         ------                  --------
>extend one ply deeper, the extension is much smaller, cause it is deeper to the
>horizon.
>

  I think, it specially means, that you extent every time you reach
    the horizon ?! (because at that case no cutoff have occured...).
  But maybe I don't fully understand what in this case is included under
  "before" and "there"... (I take the liberty to underline it in the text
    above...)

>>If my premise is true - and you are from Germany - then we are neighbours
>>- I'm from Czech...
>
>Yes, we are neighbours, but I am from AUSTRIA!!!!!!!!!
>

 So - greetings to all chess programmers, especially to those in Austria :)

    Jan

 PS: Congratulation to you for being father...



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