Displaying 20 results from an estimated 8000 matches similar to: "Random sampling while keeping distribution of nearest neighbor distances constant."
2007 Oct 03
2
Speeding up simulation of mean nearest neighbor distances
I've written the function below to simulate the mean 1st through nth
nearest neighbor distances for a random spatial pattern using the
functions nndist() and runifpoint() from spatsat. It works, but runs
relatively slowly - would appreciate suggestions on how to speed up
this function. Thanks. --Dale
library(spatstat)
sim.nth.mdist <- function(nth,nsim) {
D <- matrix(ncol=nth,
2012 Mar 22
3
How to get the input of a function right?
Hi,
I wrote a function with three inputs fun(x,y,z).
x is a matrix of three vectors combined with cbind. e.g.
x1<-(1,2,3,4)
x2<-(2,3,4,5)
x3<-(3,4,5,6)
x<-cbind(x1,x2,x3)
y is a vector e.g
y<-c(7,8,9)
z is a real number e.g.
z<-2.5
If a give the function an input like this, I get 'NA' in return. If I give
the function a vector e.g c(1,2,3) instead of 'x'
2003 Nov 05
1
fast nearest-neighbor in R?
Is fast nearest-neighbor functionality available in R?
I was thinking of something along the lines of what's
currently in S+SPATIALSTATS.
Thanks for any information anyone might have on this.
- MZ
2011 Feb 18
0
Shared nearest neighbor (SNN) clustering algorithm implementation?
Hello,
is there an implementation available for a shared nearest neighbor
(SNN) clustering algorithm?
//Jay
2002 Apr 10
0
Discriminant Adaptive Nearest Neighbor
Dear R users,
Is there anyone who is aware of a R or S package that has Discriminant
Adaptive Nearest Neighbor (DANN) classification by Hastie and Tibshirani?
I have used the search services in R website but no luck.
Thanks in advance!
Jonathan
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2007 Jul 08
0
Is there Discriminant Adaptive Nearest Neighbor classification?
Hello everyone,
Is there anyone who is aware of any R package that has Discriminant
Adaptive Nearest Neighbor (DANN) classification by Hastie and Tibshirani?
Thanks in advance!
Tracy
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2004 Jul 08
1
k nearest neighbor prediction
Hi there fellow R-users,
Does anyone know if there is a package for k nearest neighbours prediction
as opposed to classification? I have found the package knncat but can't see
a way to adjust it to predict a continuous variable.
Any help would be great,
Regards
Wayne Jones
KSS Ltd
Seventh Floor St James's Buildings 79 Oxford Street Manchester M1 6SS England
Company
2004 Feb 02
2
Nearest Neighbor Algorithm in R -- again.
Several of the methods I use for analyzing large data sets, such as
WinGamma: determining the level of noise in data
Relief-F: estimating the influence of variables
depend on finding the k nearest neighbors of a point in a data frame or
matrix efficiently. (For large data sets it is not feasible to compute
the 'dist' matrix anyway.)
Seeing the proposed solution to "[R] distance
2016 Apr 04
4
[Bug 94817] New: Nearest neighbor scaling?
https://bugs.freedesktop.org/show_bug.cgi?id=94817
Bug ID: 94817
Summary: Nearest neighbor scaling?
Product: xorg
Version: unspecified
Hardware: Other
OS: All
Status: NEW
Severity: enhancement
Priority: medium
Component: Driver/nouveau
Assignee: nouveau at
2012 May 02
2
How can a function in R handle different types of input?
Hi,
How can a function in R handle different types of input?
I have written a function, which should calculate the slope from several
3-time-point measurements by linear regression
4 three-time-point-measurements:
x<-cbind(c(1,2,3,4),c(2,3,4,5),c(3,4,5,6))
time points:
time<-c(1,3,9)
function for calculating the slope by linear regression:
fit<-function(xx,t){slope <-
2012 Jul 24
3
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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2001 Jan 10
2
nearest neighbors
Is there an implementation of a reasonable k-nearest neighbor finder
already in one of the packages?
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2013 Apr 15
2
nearest stations in distance matrix
Dear R-user,
Is there a way in R to locate the nearest 5 indices to a station, based on distances in a distance matrix. In other words i want to have nearest stations based on the distances in the matrix. The distance matrix, i have, has dimension 44*44.
Thankyou very much in advance
Elisa
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2009 Jan 09
3
create sequences from two "from" and "to" vectors
hi all,
how can I create sequences that start from a known vector, say x1 and end
with another say x2- also suppose all the sequences will be the same length.
I don't want to use a for loop
x1<-c(1,2,3,4); x2<-(3,4,5,6);
what I want is
1 2 3 4
2 3 4 5
3 4 5 6
Thanks
-----
Yasir H. Kaheil
Columbia University
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2012 Mar 11
1
Which non-parametric regression would allow fitting this type of data? (example given).
Hi,
I'm wondering which function would allow fitting this type of data:
tmp=rnorm(2000)
X.1 = 5+tmp
Y.1 = 5+ (5*tmp+rnorm(2000))
tmp=rnorm(100)
X.2 = 9+tmp
Y.2 = 40+ (1.5*tmp+rnorm(100))
X.3 = 7+ 0.5*runif(500)
Y.3 = 15+20*runif(500)
X = c(X.1,X.2,X.3)
Y = c(Y.1,Y.2,Y.3)
plot(X,Y)
The problem with loess is that distances for the "goodness of
2002 Apr 18
2
naming boxes in boxplot
Hi, this may be a too simple question, but I was not
able to find how to do it.
So when I boxplot two vectors, i.e.
x<-rbind(1,2,3,4)
y<-rbind(3,4,5,6)
boxplot(x,y)
, could somebody tell me how to name the two boxes as
apple and banana?
Thanks much,
Haun
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2003 Jun 08
6
Basic question on applying a function to each row of a dataframe
Hi,
I have a function foo(x,y) and a dataframe, DF, comprised of two vectors, x
& w, as follows :
x w
1 1 1
2 2 1
3 3 1
4 4 1
etc
I would like to apply the function foo to each 'pair' within DF e.g
foo(1,1), foo(2,1), foo(3,1) etc
I have tried
>apply(DF,foo)
>apply(DF[,],foo)
>apply(DF[DF$x,DF$w],foo)
However, none of the above worked. Can anyone help ?
2009 Dec 29
1
Effect of na.omit()
I had an NA in one row of my data frame, so I called na.omit(). But I do
not understand where that row disappeared to.
>fri=na.omit(fri)
> fri
Date.Only DAY Hour Min15 Quarter Arrival.Val Arrival4
1 09/05/2008 Friday 8 33 3 32 8
2 10/24/2008 Friday 21 86 4 28 7
3 10/31/2008 Friday 8 33 4 20
2011 Aug 18
1
CentOS 6 and IPv6 neighbor proxy
To route a subnet in ipv6 there are two possibilities:
- add route commands for the subnet in each computer
- or use neighbor proxy in the router server
I prefer neighbor proxy.
So I have to activate neighbor proxy in the router:
sysctl -w net.ipv6.conf.all.proxy_ndp=1
and I have to add entries for each client in the subnet like
ip -6 neigh add proxy
2010 Feb 24
1
Sparse KMeans/KDE/Nearest Neighbors?
hi,
I have a dataset (the netflix dataset) which is basically ~18k columns and
well variable number of rows but let's assume 25 thousand for now. The
dataset is very sparse. I was wondering how to do kmeans/nearest neighbors
or kernel density estimation on it.
I tired using the spMatrix function in "Matrix" package. I think I'm able to
create the matrix but as soon as I pass