From: Jose Andres <jaa53_at_cornell.edu>

Date: Sat 29 Jul 2006 - 08:13:30 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sat Jul 29 08:17:55 2006

Date: Sat 29 Jul 2006 - 08:13:30 EST

Hi all,

I have a set of points (1...n) each of them defined on a 3D space

(i.e. for each point I do have x,y,z coordinates), and I would like

to generate a mean pairwise geometrical distance between them. Is
there anyway I can do this with R?

Conceptually is really simple. First I have to generate a distance
matrix (let's say "distmat") of pairwise distances (d= sqrt((x1-x2)^2
+ (y1-y2)^2+(z1-z2)^2) and then calculate the mean -- mean.matrix

(distmat) -- . However, I do not know how I can generate the distance

matrix using R. I'd really appreciate all your suggestions/comments.

So, I have

x y z

1 x1 y1 z1

2 x2 y2 z2

: : : : n xn yn zn

and need

1 2 .. n 1 - 2 d12 - : n d1n d2n -

So I can calculate mean din

Thanks in advance!!!!!

Best,

/Jose

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sat Jul 29 08:17:55 2006

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