similar to: Adding a Matrix Exponentiation Operator

NAME xx - twice as dirty SYNOPSIS ~ > gem install "double x" require "xx" include XX::XHTML doc = xhtml_{ html_{ head_{ title_{ " go xx! " } } body_{ " one more and it would be illegal " } } } URI http://rubyforge.org/frs/?group_id=1024 DESCRIPTION xx is a library designed to extend ruby objects

Hi Is it possible to subset an n-dimensional array by a vector of n dimensions? E.g. assume I have > x <- array(1:24, dim=2:4) > x[1,1,2] [1] 7 > dims <- c(1,1,2) I would like a function that I can supply x and dims as parameters to, and have it return 7. Also, I would like to do something like: > x[1,1,] [1] 1 7 13 19 > dims2<- c(1,1,NA) And have a function of x and

Hi all, I'm new with R (and S), and relatively new to statistics (I'm a computer scientist), so I ask sorry in advance if my question is silly. My problem is this: I have a (sample of a) discrete time stochastic process {X_t} and I want to estimate Pr{ X_t | X_{t-l_1}, X_{t-l_2}, ..., X_{t-l_k} } where l_1, l_2, ..., l_k are some fixed time lags. It will be enough for me to compute

Hi, This is most likely only a minor technicality, but I saw the following: On page 6 of the 'parallel' vignette (http://stat.ethz.ch/R-manual/R-devel/library/parallel/doc/parallel.pdf), the random-number generator "L'Ecuyer-CMRG" is said to have seed "(x_n, x_{n-1}, x_{n-2}, y_n, y_{n-1}, y_{n-2})". However, in L'Ecuyer et al. (2002), the seed is given with

Hi, Can Someone inform me how to generate RV's using the below CDF, by inverse technique. Thanks for your help and time. My CDF is as follows \[ F(x)=0 \ \text{if} \ x < 0\]\[ F(x)=\{\frac{x-x_i}{x_{i+1}-x_{i}}*(p_{i+1}-p_{i})\}+p_{i}\ \forall \ x_{i}\leq x < x_{i+1} \] \[ F(x)=1 \ \text{if} \ x > x_{i+1} \] Regards Murthy

My parallel code is running slower than my non-parallel code! Can someone pls advise what am I doing wrong here? t and tTA are simple matrices of equal dimensions. #NON PARALLEL CODE nCols=ncol(t) nRows=nrow(t) tTA = matrix(nrow=nRows,ncol=nCols) require(TTR) system.time( for (i in 1:nCols) { x = t[,i] xROC = ROC(x) tTA[,i]=xROC } ) user system elapsed 123.24 0.07 123.47 #

Dear All, Suppose I have a vector X = (x_1, x_2, ...., x_n), X_sort = sort(X) = (x_(1), x_(2), ... , x(n) ), and I would like to know the original position of these ordered x_(i) in X, how can I do it? case 1: all values are unique x <- c( 3, 5, 4, 6) x.sort <- sort(x) # # I would like to obtain a vector (1, 3, 2, 4) which indicates that 3 in x is still the 1st element in x.sort, 5 is at

Dear R users, I'd like to compute X like below. X_{i,t} = 0.1*t + 2*X_{i,t-1} + W_{i,t} where W_{i,t} are from Uniform(0,2) and X_{i,0} = 1+5*W_{i,0} Of course, I can do this with "for" statement, but I don't think it's good idea because "i" and "t" are too big. So, my question is that Is there any better idea to avoid "for" statement

Dear R Gurus, As you probably know, dist calculates the distance between every two rows of data. What I am interested in is the actual two rows that have the least distance between them, rather than the numerical value of the distance itself. For example, If the minimum distance in the following sample run is d[14], which is .3826119, and the rows are 4 & 6. I need to find a generic way to

Hi everyone. I'm using matrix product such as : #Generate some data NCols = 5 NRows = 5 A = matrix(runif(NCols*NRows), ncol=NCols) B = matrix(runif(NCols*NRows), ncol=NCols) #First calculation R = A%*%B for(i in 1:100) { R = R%*%B } I would like to know if it was possible to avoid the loop by using something like mapply or anything else. Tx in advance, Phil -- View this message

Dear all, I know that my question is somewhat special but I tried several times to solve the problems on my own but I am unfortunately not able to compute the following test statistic using the quantreg package. Well, here we go, I appreciate every little comment or help as I really do not know how to tell R what I want it to do^^ My situation is as follows: I have a data set containing a

Hi, there. How do I calculate the cross-product in the form of \sum_{i=1}^{n}X_{i}^{t} \Sigma X_{i} using R code without using do loop? X_{i} is the covariate matrix for subject I, \Sigma is the covariance matrix. Thanks for your help. Yulei [[alternative HTML version deleted]]

I try to do single proportion test on my category data. Here is my R script: library("ctest") catSignifTest <- function( catFile ) { ############################################################### ## Get the data sets from text file catData <- read.table( catFile ) ncols <- length(catData) nrows <- length(catData[,1]) ncol1 <- ncols - 1 probeNbr

Dear mailing list, I have found some strange behaviour which I think relates to parent frames and eval. Can anyone explain what's going on here? First example: > test.parent.funcs_ function() { outer.var_ 5 subfunc1_ function() substitute( outer.var, envir=parent.frame()) print( subfunc1()) subfunc2b_ function() eval( quote( outer.var), envir=parent.frame()) print(

Hello, I am experiencing a very noticeable memory leak when using large lists of large data. The code below creates a list of matrices, yet the memory does not free up after removing that item and performing a garbage collection. Is there a something I can do to prevent this memory leak? Any help would be greatly appreciated. By the way, if you execute the code, please run it in a new R session.

I'm observing that base::sum(x, na.rm=FALSE) for typeof(x) == "double" is much more time consuming when there are missing values versus when there are not. I'm observing this on both Window and Linux, but it's quite surprising to me. Currently, my main suspect is settings in on how R was built. The second suspect is my brain. I hope that someone can clarify the below

Hola. Intento crear un archivo .html a partir de un .Rmd que tenga Toc, LaTeX y tablas. Empleo RStudio (v. 0.97.551), pero aparece un error en la función "markdownToHTML" Pasos: 1) creo un fichero Rmd (adjunto ejemplo) => con knitr (v. 1.0.5) crea un fichero ".md" 2) Si quiero añadirle el TOC (table of contents) necesito emplear la función "markdownToHTML" del

I have constructed the function mml2 (below) based on the likelihood function described in the minimal latex I have pasted below for anyone who wants to look at it. This function finds parameter estimates for a basic Rasch (IRT) model. Using the function without the gradient, using either nlminb or optim returns the correct parameter estimates and, in the case of optim, the correct standard

Dear I am using the 'as.dendrogram' function from the 'stats' library to convert from an hclust object to a dendrogram with a dataset of size ~30000 (an example code is below). I need the dendrogram structure to use the "dendrapply" and "attributes" functions and to access the child nodes, I do not need any of the plot properties. The problem is that it

Hello, I was wondering if someone knows the formula used by the function lm to compute the t-values. I am trying to implement a linear regression myself. Assuming that I have K variables, and N observations, the formula I am using is: For the k-th variable, t-value= b_k/sigma_k With b_k is the coefficient for the k-th variable, and sigma_k =(t(x) x )^(-1) _kk is its standard deviation.