Re: [Rails-devel] Tile Database API & route calculation

[John A. T. <ja...@ja...>]

Erik Vos wrote:

>I guess it's mostly a matter of words.
>To me, the Track, Junction and Station objects *are* the connectivity graph.
>Our difference then is, as it seems to me, that you restrict the cloning 
>to those Track, Junction and Station objects, not including 
>the parent tile itself. Not much saving, I would think.
>
>Or does your graph consist of entirely different objects?
>  
>
If you use them as the connectivity graph, then you wind up pointing 
into Junction objects in other Tile objects, which means the Junction 
objects have to have a reference the parent Station or Tile object 
(which complicates a common superclass).  Another problem is 
maintiaining multiple connectivity graphs -- as mentioned in the first 
message you really want to have different types of connectivity graphs 
for tile laying, token placement, and route calculations.  For the 
latter, you also need to have different connectivity graphs for each 
company.

What I am proposing is a triangular (since the edges are bi-directional) 
2-D bitvector which encodes connectivity between all the things you want 
to care about.  That would be maintained totally outside the data 
structure for the tiles, which would be immutable once loaded from the 
database.  You could have as many different connectivity graphs as you 
like without a problem.

Even if you don't want to do it with a bitvector, I think you still want 
to have the connectivity graph outside the tile data structure.

-- 
John A. Tamplin					ja...@ja...
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