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Subject: Re: How to manage extensions?

Author: Jan Pernicka

Date: 06:54:23 03/22/00

Go up one level in this thread


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:
>>>
>
>All the following is only, what I do. (InmiChess)
>It sure could be done better, but also more bad...(IMHO)

   Can I see somewhere on WWW (this abbr. I know!) more information about your
   program (games played, benchmarks...)?
>
>- All Extensions together in one branch are not allowed to exceed 9 ext. (seems
>good with actiual search depths...)
>- I make check extensions always, if distance to quietsearch is less than 7 .

       So - what's maximum searching depth of your program (say, in middle
        game) ?

>- taking back a piece without changing material balance is a ext, if it is at
>the last two plies before quiet search.

      question: does "take back" mean
          - to capture the piece of the same value
       or - to capture the piece on the same field
       or something other?

>- if a pawn gets to line 7 at the horizon, I extend (and only then!)

       I can imagine the explosion when omitting the condition in brackets...

>- promotions are in the quiet search
>- if in check, also in quiet I allow all moves to get out
>- if in check, and only one move leads out I extend.

      when I return to the first point (chess extension always when less then
      7 plies to horizon...) - does this point mean that in this case you
      use ext. also higher in the tree?

>- 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?)

>- I only extend once in one depth, never twice! But i remember the extensions
>for deeper down.

      Why do you remember it when you don't extend ( statistics? :) )

>- my quiet search is no own routine. it is within my normal search, own
>movegenerator and some ifs (although ifs are bad at the new computers, but small
>code is good for cache hits..)

   This seems me good.


If my premise is true - and you are from Germany - then we are neighbours
- I'm from Czech...

  Thank you once again
                          Jan Pernicka





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