Good points. I'll do some experiments here and I'll post later.

davi

2010/12/28 Willemien <[email protected]>:
> To be complete:
>
> If you use it for endpositions  (or other plays where passes are
> reasonable moves)
>
> Then it depends on what your scoring mechanism is.
>
> For Territory scoring you also need the prisoners difference. (or the
> diference in number of passes)
>
> For area scoring this is not nescesary and i think and the "picture"
> of the board is enough.
>
> On Tue, Dec 28, 2010 at 3:30 PM, davi vidal <[email protected]> wrote:
>>    Sorry. I forgot to add that I'm storing the moves in SGF format.
>>    What I'm going to do: get a Go position (dunno how, that's why I'm
>> asking about FEN), encode in JSON, parse in JavaScript and draw in
>> HTML. As backend, I'm using Ruby, so I can have something as
>> 8b10/19/19... and parse using regex.
>>
>>    As far as I can understand from your posts and the previous
>> thread, the only drawback is the *ko rules/repetition that I *will*
>> miss with FEN, right?
>>
>> davi
>>
>> 2010/12/28  <[email protected]>:
>>> It depends on what you want to do with the representation. Usually a go
>>> programmer only needs to match the current position with an old one either
>>> to implement super ko correctly or perhaps updating some statistics for the
>>> position like in an opening database.
>>>
>>> For this purpose using a standard 64-bit Zobrist hash code where you simple
>>> xor together a random 64-bit integer each stone on the boards and for
>>> example the direct ko or who is to play. Thus you need only store 8 byte for
>>> each position + whatever extra you want to associate with it.
>>>
>>> But you cannot reconstruct a position from the Zobrist code, so if you need
>>> to access what the board actually looked like i guess you need to use at
>>> least 2bit per possible stone, unless you make it really compressed.
>>>
>>> Does it have to be human readable? I guess this what you want when I reread
>>> your post.
>>>
>>> A more standard way in my thinking is to not store the position but simply
>>> list the moves that lead to the position, for example the standard SGF file
>>> format which is then universally portable as well. I am not used to FEN
>>> notation in chess so I do not know what uses it has.
>>>
>>> Well that was at least some alternatives that would be standard for a go
>>> programmer but maybe you need something new and then perhaps you are the
>>> first to do it.
>>>
>>> Oh, where are also standard pure text ascii diagrams that for example gnugo
>>> and gogui can read and export. You might have a look at that too. This is
>>> from Gogui:
>>>
>>>   A B C D E F G H J
>>>  9 . . . . . . . . . 9
>>>  8 . . . . O X . . . 8
>>>  7 . O O O + X + O . 7
>>>  6 . X X . X . X O . 6
>>>  5 . . + . X X O . . 5
>>>  4 . . . . . . O . . 4
>>>  3 . . + X + O + . . 3
>>>  2 . . . . X . . . . 2
>>>  1 . . . . . . . . . 1
>>>   A B C D E F G H J
>>> Black to play
>>>
>>> But this may lack complete state information. I do not know if there are
>>> some proper definition of this.
>>>
>>> Best
>>> Magnus
>>>
>>>
>>>
>>> Quoting davi vidal <[email protected]>:
>>>
>>>>   Hello everyone. I'm new to this list.
>>>>
>>>>   Sorry for resurrect such old thread, but after read it all, I can't
>>>> reach a conclusion: is there anyway to represent a Go position?
>>>>
>>>> http://www.mail-archive.com/[email protected]/msg05749.html
>>>>
>>>>    I'm aware about the *ko rules and that I can't say if the current
>>>> position already happened in the game.
>>>>
>>>>    My problem: I just need to store the current position in the game
>>>> plus the side to move. Is FEN sufficient? Also, if I need to deal with
>>>> *ko rules/repetition, I'm considering store all positions, since the
>>>> worst scenario (from file size perspective) would be the entire board
>>>> covered plus a ko point:
>>>>
>>>>
>>>> bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb/bbbbbbbbbbbbbbbbbbbb
>>>> b s19
>>>>
>>>>    This FEN file have 428 bytes. Assuming 300 moves, I would spend
>>>> 130 kB. Storage isn't my problem here.
>>>>
>>>>    So, my question is: is my approach reasonable? What would you
>>>> recommend otherwise?
>>>>
>>>>    Again: sorry for resurrecting such old thread, but I couldn't find
>>>> any "Search archives" function. Also, sorry about my poor English.
>>>>
>>>>    Regards,
>>>>
>>>> davi
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>>>>
>>>
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