similar to: Fourier Transform

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"),

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

Dear R gurus and users, I seem to have problem finding the right tool for plotting convex hulls over 2D plots, after a cluster analysis. In fact I would like to draw a convex hull in 2D for a generic group of points. I found a "convhulln", but this doesn't seem to give me a convex hull. Here is what I do: > library(mvtnorm) > Mean <- c(2,1) > Sigma <-

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)) }

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

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

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

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

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

Dear R Helpers, Is there any literaure available (including R code) on Fast Fourier Transform being used in CreditRisk+? I need to learn how to apply the Fast Fourier Transform. I agree I am too vaue in my question and sincerely apologize for the same, but I am not able to understand as to where do I start for this particular assignment. I tried to search google for CRAN and Fast Fourier

Dear list, I am trying to choose the scale parameter for the cgt transform but I don't know how to do it. In time I would like to be able to separate points 30 samples apart, and in frequency I would like to separate bands 0.04 Hz apart. I tried the two approaches described below and they gave me different results. I would appreciate advise on how to do this. The Rwave Gabor transform uses

I did a fourier transform on a function in time domain to get the following functions in frequency domain (in latex): $Y_1[\omega] = \frac{1}{1-\phi_1 e^{-jw}}$ $Y_2[\omega] = \frac{1}{1-(\phi_1 + \phi_2)e^{-jw} +\phi_1\phi_2e^{-2jw}}$ How do I find the spectrum of this function for given $\phi_1$ and $\phi_2$ coefficients and in the discretization interval $w = [-\pi:.1*\pi: \pi]$? Then, how

Dear all, I work with (vibrational) spectra: some kind of intensity (I) over frequency (nu), wavelength or the like. I want to do fourier transform for interpolation, smoothing, etc. My problem is that the spectra are often irregularly spaced in nu: the difference between 2 neighbouring nu varies across the spectrum, and data points may be missing. Searching for discrete fourier transform

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

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

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

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

Hi All, Here is the problem: I'm trying to generate a number of Fourier Descriptors figures for an experiment. All I need is that they are created within a loop and saved with sequential names (e.g., s1_1.png, s1_2.png etc..) in my directory. I created a nested loop with a counter for the different amplitudes for the actual shapes and a counter for the file names. This script: *count

Dear R-help members, To whom it may concern, our research group is conducting a study to evaluate the predictive value of 24 hour blood pressure variability. We are looking for an R routine that performs a fast Fourier transform spectral analysis (with an output of the approximation function of the Fourier and estimates the validity of the model for the various harmonics). Thanks Vittorio

Hi Guys, I had a monthly time series's data of land temperature from 1980 to 2008. After plotting a scatter diagram, it seems that annually, there is a semi sinusoidal cycle. How do I run Fourier's series to the data so that I can fit model on it? I am really sorry for my question sound stupid, but I just don't know where to start. I am desperately looking for help from you guys.