similar to: [slightly off topic] Sweave with markdown

DeaR list, I happily use eigen() to compute the eigenvalues and eigenvectors of a fairly large matrix (200x200, say), but it seems over-killed as its rank is limited to typically 2 or 3. I sort of remember being taught that numerical techniques can find iteratively decreasing eigenvalues and corresponding orthogonal eigenvectors, which would provide a nice alternative (once I have the

Hello R list, I have two matrices of identical dimensions, and I want to fit a straight line for each pair of columns and plot the resulting lines. I got it to work with a for loop, but there must be a better way, > n<-5 > N<-10 > > data.x<-matrix(1:(n*N),ncol=n) > data.y<-matrix(1:(n*N) + rnorm(n*N,sd=1),ncol=n) > >

Dear all, The following example code produces a graph with ggplot2, to which I add several vertical lines of arbitrary colors. I am not satisfied with the legend: it automatically adds some vertical lines which I'd rather not see (they confuse the reader rather than add information in this case). > library(ggplot2) > dfr <- data.frame(values = sin(1:50/10), > fact =

Hi, I need to create a text file in the following format, > 1 100.0 0 > 0 0 > 1 1 > 0 0 > 1 1 > # > 1 100.0 0 > 0 0 > 0 1 > 1 0 > 1 1 ... where # is part of the format and not a R comment. Each block (delimited by #) consists of a first line with three values, call it dose, and a list of (x,y) coordinates which are a matrix or data.frame, >

Dear list useRs, I have to generate a random set of coordinates (x,y) in [-1 ; 1]^2 for say, N points. At each of these points is drawn a circle (later on, an ellipse) of random size, as in: > N <- 100 > > positions <- matrix(rnorm(2 * N, mean = 0 , sd= 0.5), nrow=N) > sizes<-rnorm(N, mean = 0 , sd= 1) > plot(positions,type="p",cex=sizes) My problem is to

Hi, I've started my own (first) package, part of which consists in listing common physical constants (Planck's constant, the speed of light in vacuum, etc). I'm wondering what would be a good way of dealing with pairs of value/unit. > constants <- list( cel = 2.99792458e8 , #m/s > Z0 = 376.730313461, #ohm > eps0 = 8.854187817e-12,#F/m > mu0 = 4*pi*1e-7,#N/A^2

DeaR list, I'm a bit lost in the behavior of substitute and co. I often use fairly long axis labels in my graphs (long to write, that is). Typically, they would contain some greek letters and units with exponents, as in: > xlab=expression(paste("text ", alpha, " / ", V,".", m^{-3}, ".", > kg^{-2}, ".", l^{4})) To make this a

Dear R list, I'm having difficulties in choosing between a list or a data.frame, or an array for the storage and manipulation of my data (example follows). I've been using the three for different purposes but I would rather like to know which is more adapted to what task. Here is the data I'm currently working on: 200 observations, each observation being a vector of length

Dear R helpers, I'm trying to write a numerical scheme for a boundary integral method to solve an electromagnetic problem. This requires the computation of the distance between points at the surface of an object (a sphere, in my example). Here is my code, > require(rgl) > r<-1 > size<-10 > theta<-seq(0,2*pi,length=size*2) > phi<-seq(0,pi,length=size) > pc

Hi, I have two small issues with my R code, no big deal but curiosity really. Here is a sample code, > > x <- rnorm(1:10) > > foo <- function(a = 1, b = list(x = c(1:10), y = c(1:10))){ > > for (ii in seq(along=b$y)){ > > print(x[ii] + b$x[ii]) > } > > > } > > foo() # default OK > > foo(b=list(x=1, y=c(1:10))) # only the first

Hi Folks... No code to troubleshoot here. I need some suggestions about the right terminology to use in further searching, and any suggestions about R pkgs that might be appropriate. I am in the planning stages of a project in which IR, NMR and other spectra (I'm a chemist) would be collected on various samples, and individual samples would be followed over time. The spectra will be feature

Dear R helpers, I've successfully created a package 'constants' using package.skeleton () with one dataframe and a few functions. However, now that I want to add some functions and data to the package, I run into a problem. I ran prompt(...) and moved + edited the resulting .Rd files as appropriate (I believe). The log file from RCMD check constants does indicate a few

Dear all, I'm puzzled by the following example inspired by a recent question on R-help, cc <- textConnection("user_id website time 20 google 0930 21 yahoo 0935 20 facebook 1000 25 facebook 1015 61 google 0940") d <- read.table(cc, head=T) ; close(cc) table(d$user_id) # count the

Dear R users, I'm porting a piece of Matlab code to R, but I'm now stuck with the following: I need an equivalent of besselJ(x, nu) that can handle a complex argument x. I couldn't find any R implementation. I did find a possible fortran solution in SLATEC (< http://www.netlib.org/slatec/ > , CBESJ-C), however I've never tried to use external C or Fortran code

Dear R users, I'm porting a piece of Matlab code to R, but I'm now stuck with the following: I need an equivalent of besselJ(x, nu) that can handle a complex argument x. I couldn't find any R implementation. I did find a possible fortran solution in SLATEC (< http://www.netlib.org/slatec/ > , CBESJ-C), however I've never tried to use external C or Fortran code

DeaR list, Pardon the stupidity of this question but I've been trying this for a while now without success. I've followed the example given in the green book "programming with data", and I now have a working example of a S4 class with a few methods (plot, summary, as.data.frame). It's all very nice in one file, but I cannot find the way to put this information in a

DeaR list, I'm running an external program that computes some electromagnetic response of a scattering body. The numerical scheme is based on a discretization with a characteristic mesh size "y". The smaller y is, the better the result (but obviously the computation will take longer). A convergence study showed the error between the computed values and the exact solution

Dear List, I'm stuck on what seems like a simple indexing problem, I'd be very grateful to anyone willing to help me out. I queried a dataframe which returns a character vector called "plot". I have another dataframe from which I want to subset or select only those rows that match "plot". I've tried subset, and also the "which" command. plot

Dear all, Happy new year! I posted a very similar question a few days ago, but probably too cluttered. Here is a tidy, minimal version: I want to make a package, with a data.frame d and a function f given below. Now, the function f needs to use the data.frame d. I could (and that's what I've done temporarily) make a local duplicate of this data.frame in the function definition,

Dear list, I have the following example, from which I am hoping to retrieve numeric values of the factor levels (that is, without the brackets): > > x <- seq(1, 15, length=100) > y <- sin(x) > > my.cuts <- cut(which(abs(y) < 1e-1), 3) > levels(my.cuts) hist() does not suit me for this, as it does not necessarily respect the number of breaks. getAnywhere