[pbmserv-dev] Re: [pbmserv] Palago notation?

[Richard Rognlie <rrognlie@gamerz.net>]

The board grows, and spaces around the board grow.  
placed.  

Take the tiled board, and pad it with the 2 spaces in every direction

Then from the Northwestern most "row"... start counting.   moving
north easterly until you have no more move locations in that row.
Move down a row..

e.g. for the following board (where X's indicates where a tiles is
and . == where a placement can occur)

                          
                        .     
                    .       .     
                .       .       .     
                    .  ___  .       .     
                .     / X \___  .          
                    . \___/ X \     .      
                .     / X \___/ .       .  
            .       . \___/ X \___  .      
                .  ___/ X \___/ X \     .  
            .     / X \___/ X \___/ .      
                . \___/ . \___/ .       .  
            .       .       .       .      
                .       .       .              
                    .       .                  
                                 
                              

would yield the location notation of...

                          
                        3     
                    2       7     
                1       6      12     
                    5  ___ 11      17     
                4     / X \___ 16          
                   10 \___/ X \    21      
                9     / X \___/20      26  
            8      15 \___/ X \___ 25      
               14  ___/ X \___/ X \    32  
           13     / X \___/ X \___/31      
               19 \___/24 \___/30      36  
           18      23      29      35      
               22      28      34              
                   27      33                  
                                 

No ambiguity.  No arbitrary start location.


                              

                      
On Mon, Sep 21, 2009 at 04:37:53PM +1000, John Farrell wrote:
> I've been thinking about such a system as part of my vague dreams of
> writing a Palago bot. Ideally a solution would:
> 
> (a) not change the description of the location of a particular piece
> just because other pieces were added later
> 
> but that means that you can't have
> 
> (b) equivalent board positions have identical descriptions.
> 
> I guess to describe the progress of a game you need (a), but to index
> a library of game positions you need (b). My gut instinct is that we
> would need a system which describes the position of a piece as a
> series of steps from the start position, e.g. if the start position is
> defined as X, then the locations in the six directions from there are
> x0, x1, x2, x3, x4, x5. From then on you tack on another digit, but
> positions can have multiple names, e.g. x01 is the same as x10, and
> x03 is the same as x. You then need to canonicalise the location
> descriptions. That would give you (a).
> 
> To achieve (b) you need some algorithm to canonicalise whole board
> descriptions. Choosing x is a bit tricky - maybe you'd need to
> calculate some sort of centre of gravity to identify a start location,
> and somehow figure out a rotation from which the board is to be
> viewed, e.g. the direction in which the board extends furthest.
> 
> This is the most thinking I've done in this direction, but if anyone
> wants to proceed I'm keen.
> 
> 
> John
> 
> On Sat, Sep 19, 2009 at 8:53 AM, David J Bush <twixt@cstone.net> wrote:
> > | > Could someone please define for me the space numbering
> > | > scheme used in Palago here on Gamerz? Thanks.
> > |
> > | Essentially random. ?The possible spaces are renumbered each turn.
> > | ?You can't tell anything by looking at the notation.
> > | ?It's the saem with all of Cameron's boardless games.
> > | ?Would you like to suggest a better system?
> >
> > Well I doubt Cameron made use of any random value generator in
> > his program. Renumbering the spaces is fine, as long as this is
> > done in a consistent manner, otherwise, as you point out, the
> > whole purpose of a notation system is defeated. Cameron's
> > algorithm is deterministic, but it's not easy for the user to
> > determine what it is. So, I would suggest a scheme which IS easy
> > to understand. For example, label the vacant spaces in the
> > leftmost column top to bottom, then the next column to the right
> > top to bottom, etc. until you reach the bottom space of the
> > rightmost column.
> >
> >
> > To unsubscribe, send a message to esquire@gamerz.net with
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> >
> >
> 
> 
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