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Subject: Re: How you judge in your program: "opening", "middle game", "end game"

Author: Shep

Date: 09:31:29 01/28/00

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On January 28, 2000 at 11:31:29, Amir Ban wrote:

>On January 28, 2000 at 05:25:26, Shep wrote:
>
>>On January 27, 2000 at 10:40:05, Jari Huikari wrote:
>>
>>>Where you consider the position of a game changes to middle game / end game?
>>>
>>>opening == most pieces haven't moved yet ? / opening book not ended yet ?
>>>end game == few pieces left ?
>>>middle game == neither of the two above ?
>>
>>I suppose some programs have a more fine-grained approach to this.
>>Tiger for example divides the game into several "phases" (more than 3 for sure
>>:) according to the material on the board, and different evals
>>(/extensions/pruning/...?) are fired off according to the phase the program is
>>in.
>>In the DOS version, it would show "Phase x/y"; in Rebel Tiger, the best way to
>>see it is when the eval suddenly jumps from like "+1.10" to "+0.20" (or vice
>>versa) after a capture has occurred. (Contrary to Fritz, this is _not_ due to
>>any preprocessor oddities. :)
>>
>
>Why isn't it like Fritz ? It sounds exactly the same.

It does not happen to Tiger that he says "+0.00" and then after the next
capture, shows "-3.00" immediately. That would be a result that has been
reported repeatedly about Fritz. Tiger's eval may go up or down a bit, but it
does not miss losing moves just because it was "in the wrong phase".
So I suppose there's a difference between the preprocessing Fritz employs and
the things Tiger does between phases.

Of course I cannot point the finger to it, not knowing either program's source
code, but I figure that Tiger's approach is different (besides, such drastic
eval changes (1 pawn or more) are _extremely_ rare for Tiger).

---
Shep





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