RE: Minimum spanning circles and Voronoi diagrams

["Creager, Robert S" <CreagRS@LOUISVILLE.STORTEK.COM>]

> -----Original Message-----
> From: Chris Albertson [mailto:chrisalbertson90278@yahoo.com]

Yes and no.  Like you, I'm keeping track of running count.  My plan was(is)
once a star has N observations, freeze the location in one table, where you
match to, while adjusting another table, in which the mean will move.  I
kind of have this in place.  The no part comes from using all historical
data every time a new point is added.  This I'm not doing.  What I was doing
is at some point in time, use all the historical data to determine what's
going on with it, but only when desired.  I agree 100% with your last
statement.

> 
> OK, I finaly caught on.  You are solving this for a group of N
> stars.  I did it diferently.  I had a set of observations that I
> called "one star"  I defined the location as the mean of all
> observations in the set.  My problem was to decide it the
> next observation was to be added to the set or if it was to
> be the start of a new set.  If I added it I'd update the
> location of the set.  Over time the mean location stayed
> put.
> 
> The reason I did this was because I did not want to have to
> read up all that historic data every time one new point
> was added.  I could update the running count, means and sigmas
> without accessing all the old data points.  Much faster.
> 
> Your method could be better but what? 50X slower?  I think in
> a production evironment, use my faster method then come back
> later and use the more powerfull technique where there is
> some indication we have a double.