Nearest Neighbors

I was wondering if there is a way in R to find k nearest neighbors of
various
orders, say order 2, 3, or 4. In otherwords neighbors of neighbors of
neighbors. You get the idea. I know that I can use
knearneigh(matrix.data,
k) but this only gives me the k nearest neighbors and not of a
particular
order. 


Thanks in advance. 



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library(FNN)
set.seed(42)
x <- rnorm(100, 50, 15)
y <- rnorm(100, 50, 15)
dat <- data.frame(x, y)
knns <- get.knn(dat, k=4)
str(knns)
knns.ndx <- data.frame(knns[["nn.index"]])
head(knns.ndx)

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of olemissrebs1123
Sent: Tuesday, July 24, 2012 1:27 PM
To: r-help at r-project.org
Subject: Re: [R] Nearest Neighbors

I don't see the "obvious" portion. What I am looking for is an output
that
gives me an n*k matrix n (x,y) pairs k neighbors but using order say 4.



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Neighbors-tp4637618p4637648.html
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I was wondering if there is a way in R to find k nearest neighbors of various
orders, say order 2, 3, or 4. In otherwords neighbors of neighbors of
neighbors. You get the idea. I know that I can use knearneigh(matrix.data,
k) but this only gives me the k nearest neighbors and not of a particular
order. 

set.seed(42)
x <- rnorm(100, 50, 15)
y <- rnorm(100, 50, 15)
dat <- cbind(x, y)
library(spdep)
nn <- knearneigh(dat, 1)
nn1 <- nn$nn # Nearest neighbors
nn2 <- nn1[nn1] # Nearest neighbor of the nearest neighbor
nn3 <- nn2[nn1] # Third order
nn4 <- nn3[nn1] # Fourth order
head(cbind(nn1, nn2, nn3, nn4), 10)

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of Petr Savicky
Sent: Sunday, July 29, 2012 1:44 PM
To: r-help at r-project.org
Subject: Re: [R] Nearest Neighbors

On Tue, Jul 24, 2012 at 09:26:49AM -0700, olemissrebs1123 wrote:

I was wondering if there is a way in R to find k nearest neighbors of

various

orders, say order 2, 3, or 4. In otherwords neighbors of neighbors of
neighbors. You get the idea. I know that I can use

knearneigh(matrix.data,

k) but this only gives me the k nearest neighbors and not of a

particular

order.

Hi.

If i understand correctly, then this may be achieved by several
iterations.
In the first iteration, the nearest neighbours are found. The next
iteration
starts from them a finds their nearest neighbours. These are neighbours
of
order 2. A general iteration finds neighbours of order n by looking for
neighbours
of the points found in the previous step, which are the neighours of
order n-1.

Hope this helps.

Petr Savicky.