[Repast-developer] Re: hex space

[Nick C. <vze...@ve...>]

See below.


On Mon, 2001-11-19 at 09:59, Laszlo Gulyas wrote:
> 
> On the other hand, I think, the idea of a Discrete 2D space must be much
> broader than just grids with the two neighborhoods above. I can think of more
> than just the hexagonal spaces as an addition.

Your right. That's why I'd like to have a new space library that
eventually replaces the old. 

> 
> >On your ideas about defining Grids and Torii via their neighborhood
> >behavoir (e.g. Object2DMooreGrid), this is reasonable as far as client,
> >that is, agent behavoir code is concerned. For those of you just tuning
> >in, the idea here is that agent behavoir stays the same (i.e
> >getNeighbors()) across a variety of spaces. My concern though is that
> >now the setup code will have to change according to which space is
> >required, and I'm not sure what is gained in the short term. You are
> >correct about the long term though, tools with menus etc.
> 
> I think, only one part of my point is that the alternate design would allow
> the use of tools with menus. More importantly, however, I think that the
> neighborhood model is _really_ an identifying part of the space. A grid
> with Moore neighborhood is just _not_ the same as a grid with von Neumann
> neighborhood.

I agree with you, but (there's always a but) when I originally wrote the
space library I was incorrectly thinking of spaces as merely collections
and the neighborhood code as various ways to get elements from those
collections (in the same way that you can do pop() and some what
inchorently get(int index) on a java.util.Stack). The current library
doesn't reflect the neighborhood model as an identifying part of the
space. This was poor design on my part, not fully understanding the
agent modeling domain. A re-design of the space library would take this
into account.

> >I'm willing to make major additions and within reason some changes to
> >the current space library. What would be nice is a new architecture
> >along the lines of what you've been talking about that could be used in
> >conjunction with the current one. The current space code could be
> >deprecated, although perhaps not in the java sense, and users would be
> >encouraged to use the new one. If you'd like to take the lead on this,
> >feel free.
> 
> I am not sure I understand this. Are you thinking of a completely disjoint
> space hierarchy, or space classes that implement several interfaces or
> something comletely different?

What I'm thinking is a new design nearly from scratch and this would
also require new gui displays classes as well. You've pointed out
several conceptual problems in the space library and I don't think these
can be rectified by shoe-horning in new code, especially if we want to
incorporate the ideas from your longer musings on spaces.

Nick

-- 
Nick Collier 
Social Science Research Computing
University of Chicago 
http://repast.sourceforge.net