Re: [Repast-developer] Re: Repast-developer digest, Vol 1 #24 - 2 msgs

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

On Fri, 2001-11-30 at 21:46, Laszlo Gulyas wrote:
> Hi,
> 
> I am not sure I completely understood everything in these mails below
> (I have little clue about GIS's), but they certainly sounded interesting.
> 
> Could you explain me at some length what a congruency matrix is?
> And I am ashamed to ask, but I am not sure I understand the centroid
> thing either... ;-)
> 
> Finally, how is geometry represented in standard gis software? I mean, maybe
> we could borrow something from there, too . I am fine with ArrayList, but 
> who knows...
> 
> On the other hand, I have a couple of less visionary 'proposals', too. All
> of these are just quick ideas, so feel free to point out the defects in them.
> 
> - I tend to like the use of ObjectLocation in the multi-occupation grids.
>    Maybe, we should provide this functionality in all discrete grids.
>    (I am lacking it when I want to implement moving -- it's OK that I can
>     grab my neighbors, but it would also be nice if I could grab the 
> neighborous
>     cells/locations, too.)

I was hoping to do this soon after I wrote the multi-occupancy grid, but
I never got around to it. Its still on the list, but feel free to do it
yourself, if you have the time :).

> 
> - Also, I would propose to introduce another standard functionality. Something
>    like DistanceFromTo()... This is because while calculating the distance 
> on normal
>    grids is fairly easy, it can get rather complicated in other cases. (The 
> hexagonal
>    lattice is one example, but I can also think of a subclass of the normal 
> 2DGrid,
>    which contains walls and other obstacles...)
> 
> - Finally, in Node (in the networking library), it would be nice to have 
> something
>    like getEdgeTo(Node), which would return the edge that connects the 
> actual node
>    to the parameter (or null).

I added a some new methods along this line to DefaultNode last thurs.
and can certainly add this as well. However, these new methods recognize
that a node may have multiple edges to or from another node. For
example, a son may have a business link and a family link with his
father. Internally there is now a HashMap with nodes as keys and a
HashSet of edges as values. Given this, what would be better do you
think --

public Iterator getEdgesTo(Node node)

or 

public HashSet getEdgesTo(Node node)


Nick


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