Displaying 20 results from an estimated 800 matches similar to: "convex hull for cluster analysis"
2010 Jul 07
2
how to define method for "+" function in a new class
Dear R developers,
I have a new class, which I called "Molecule", and have tried to define =
a "+" operation for 2 objects of this class.
This is what I have written so far, although the method is not complete =
(I'm trying to look at it at intermediate stages):
setMethod(
f=3D"+",
signature(x=3D"Molecule",y=3D"Molecule"),
2009 Dec 10
1
question about centroid-linkage (cluster analysis)
Dear R community,
I would be greatful if somebody could shed light on the following.
I have created a set of 6 points to check how centroid
agglomeration works in cluster analysis:
> Y <- data.frame(x=c(-1,1,1,-1,10,12),y=c(1,1,-1,-1,0,0))
It is quite intuitive to understand that the last clusters to be joined will be
{1,2,3,4} with {5,6}. Now, the centroid for the first cluster has
2010 Jul 23
1
greek letters in rgl plot3d
Dear RGL experts,
I haven't been able to add greek letters to my rgl plot3d.
I have tried "expression" with no success.
Here is the interested bit:
> library(rgl)
> cb <- cube3d()
> plot3d(cb,xlab=expression(alpha),ylab="",zlab="",box=FALSE,alpha=0.5)
The expression(alpha) appears as "alpha", rather than as a greek symbol.
I suspect greek
2010 Sep 09
1
rgl and lighting
Dear R community (and Duncan more specifically),
I can't work out how to make additional light sources work in rgl.
Here is the example.
First I create a cube and visualize it:
> cubo <- cube3d(col="black")
> shade3d(cubo)
Next I position the viewpoint at theta=0 and phi=30:
> view3d(theta=0,phi=30)
Next, I want to create a 2nd light source which diffuses red light
2011 Feb 26
2
sourcing a linux file with "system"
Dear R community,
I would like to source a file in my linux system to set a few environment variables.
I have tried:
> system("source /home/james/build//ccp4-6.1.13/include/ccp4.setup")
and got:
sh: source: not found
In fact, using Sys.which("source") I get an empty string.
How can I source that ccp4.setup file from within an R session?
J
Dr James Foadi PhD
Membrane
2010 Jan 25
1
summing a large, partitioned data frame
Dear R community,
I'm trying to develop a fast way of summing specific rows of a large data frame.
Here is an example of the kind of data frames I'm dealing with:
> refls
H K L M/ISYM BATCH I SIGI
43247 1 0 5 21 79 61.44117 2.20553
1040 1 0 5 257 6 15.16316 0.54431
2324 1 0 5 257 5 46.76152 1.67858
31515 1 0 5 259 60 57.97305
2007 Jul 05
3
unexpected result in function valuation
Dear all,
I have a very small script to plot a function. Here it is:
##########################################
sinca <- function(N,th)
{
return(sin((N+0.5)*th)/sin(0.5*th))
}
plot_sinca <- function(N)
{
x <- seq(-5*pi,5*pi,by=pi/100)
y <- rep(0,length=length(x))
for (i in 1:length(x))y[i] <- sinca(N,x[i])
plot(x,y,type="l",ylim=c(0,2*N+4))
return(c(x,y))
}
2008 Jun 05
2
Fourier Transform
Hello All,
I wanted to perform a fourier transform on high frequency financial data. I
have searched and have not found much on this topic for R. I was wondering
if anyone has used any libraries for it or have come across any papers I may
read.
Many Thanks,
Neil Gupta
[[alternative HTML version deleted]]
2008 Mar 17
1
problems with rgl in Ubuntu 'gutsy'
Dear R users/gurus,
I have recently installed Ubuntu 7.10 (Gutsy) on my Dell Latitude D520.
First time for me, as I have always used Fedora.
R installation using "apt" has proceeded fine, both for r-base and r-base-dev.
Next, I need to install various other packages, "rgl" being first in the line.
I have sorted some preliminaries by installing headers for X11 and Mesa:
sudo
2008 Oct 08
0
issues with "write.table"
Dear R gurus and users,
I'm having problems with the use of write.table.
I have a 28-variables data frame create at each cycle of a loop; it can contain between 2000 and 3000 rows for each cycle.
After each cycle the data frame is written out to a file with the "append=TRUE" option and then removed from memory.
These are the couple of lines involved:
> data2 <-
2007 May 31
1
recompile R using ActiveTcl
Dear all,
While running some code requiring the "tcltk" package I have realised that my
version of R was compiled with the Tcl/Tk libraries included in Fedora 6. It
would be for me better to use the ActiveTcl libraries (which I have
under /usr/local), and I'm aware that this probably means to recompile R with
the proper configuration variables.
But...is it by any chance
2010 Jan 18
0
new R package. How to hide data file
Dear R community,
I'm in the process of writing a package.
One of the functions reads a whole ascii file, full of data:
> SYMINFO <- scan("/file/full/of/data.txt",what="character",sep="\n",quiet=TRUE)
SYMINFO is now an array character with roughly 14000 elements.
I thought the best way to use this file in the package was to list it, together with the
2007 Sep 07
1
Finding convex hull?
Dear UseRs,
I would like to know which function is the most efficient in finding
convex hull of points in 3(or 2)-dimensional case?
Functions for finding convex hull is the following:
convex.hull (tripack), chull (grDevices), in.chull (sgeostat),
convhulln (geometry), convexhull.xy (spatstat), calcConvexHull
(PBSmapping).
I also would like to know if there is a function that can be used
2008 Feb 06
3
counting row repetitions without loop
Hi,
I have a data frame consisting of coordinates on a 10*10 grid, i.e.
> example
x y
1 4 5
2 6 7
3 6 6
4 7 5
5 5 7
6 6 7
7 4 5
8 6 7
9 7 6
10 5 6
What I would like to do is return an 10*10 matrix consisting of counts
at each position, so in the above example I would have a matrix where,
for example, cell [4,5] contains 2 and [6,7] contains 3. At the
2009 Dec 04
1
multidimensional point.in.polygon??
Hi,
I seek to identify those points in/outside a multidimensional convex hull
(geometry::convhulln). Any suggestions?
Background just in case I'm going down a really wrong road:
Given an observed data set with one dependent/observed variable (Y) and
multiple (3 to 10) independent/design variables (X1, X2, ...) I want to
increase the number of points by interpolating. I'm using
2014 Apr 14
2
PXE booting UEFI
Good Afternoon,
As per the installation guide, section 30.2.2 I?ve created an efidefault file at /var/lib/tftpboot/pxelinux/pxelinux.cfg/efidefault
However, this file is never requested by the 64 bit PXE loader (bootx64.efi), as shown by tcpdump:
75 RRQ "/pxelinux/42272635-0011-5053-ACF2-82A100E615F2" octet tsize 0 blksize 512
59 RRQ "/pxelinux/01-00-50-56-A7-BA-BF"
2006 May 03
6
Xen Installation
Hi,
I am installing xen first time.
Install in suse linex 9.3 & red hat se 4.3 but i could
not start xen domain.
I have installation guide tar files & rpms of xen 3.0.
but still i am not able co to configure xen 3.0.
can some body help me how to configure xen.
Awaiting for reply.
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2020 Feb 06
4
No announcement for kernel 3.10.0-1062.12.1.el7
On our CentOS 7 servers I see there is a new kernel available when doing
yum update:
kernel 3.10.0-1062.12.1.el7
kernel-devel 3.10.0-1062.12.1.el7
However I am not able to find any announcement at redhat.com for this
kernel. The only announcement I find is this from CentOS:
https://www.mail-archive.com/centos-announce at centos.org/msg11573.html
However that CentOS announcement links to
2013 Oct 17
3
Speeding up configuration log regeneration?
Hi,
We run four-node Lustre 2.3, and I needed to both change hardware
under MGS/MDS and reassign an OSS ip. Just the same, I added a brand
new 10GE network to the system, which was the reason for MDS hardware
change.
I ran tunefs.lustre --writeconf as per chapter 14.4 in Lustre Manual,
and everything mounts fine. Log regeneration apparently works, since
it seems to do something, but
2008 Jul 19
1
estimating volume from xyz points
Dear all,
I have several sets of x-y-z points and I need to estimate the volume that
encompass all my points.
Recently I got some adivice to show the "convex hull" of my points using
geometry package (see code below).
But now I need to calculate the volume of my set of points.
Any advice are wellcome.
Thanks in advance
Miltinho Astronauta
Brazil
-----
require(geometry)
library(rgl)