similar to: function to remove attributes?

Dear list, I have tried to setup my Xemacs for use with Sweave, which I indend to learn. I have followed the instructions in the Sweave FAQ, that is to say, I put (defun Rnw-mode () (require 'ess-noweb) (noweb-mode) (if (fboundp 'R-mode) (setq noweb-default-code-mode 'R-mode))) (add-to-list 'auto-mode-alist '("\\.Rnw\\'" . Rnw-mode)) (add-to-list

Hi, I am about to but a laptop, and have narrowed the choices down to a Dell Latitude 600 and an Apple Powerbook G4 Aluminium (Princeton provides these models at a discount for grad students). I am biased towards the Powerbook, and would like to run Debian on it. I have only used debian on i386 platforms so far. I use R quite frequently, so I would be interested in your experience of running R

I need to find a computationally simple process for the movement of interest rates. In this simplified model, an interest rate can have 3--5 possible values, and its movement is characterized by a matrix of transition probabilities (ie, it is a Markov process). I would like to estimate this process from a given set of data. For example, let the interest rate time series be: 7 3 8 2 5 9 6

Hi, I am plotting a policy function (result from a dynamic stochastic optimization problem, discretized approximation). The policy function maps from an 2 x 2 x 2 x 3 x B x F state space to a B x F state space (B and F are usually between 4-6, and represent domestic and foreign savings. The other variables are income (Y), inflation (Pi), domestic and foreign interest rates (R and Z)). I

Is there a way in R to test if a given number is an integer, ie a whole number? I am not referring to the data type of a number, but to its value. That is to say, is.whole(pi-pi+2) would be TRUE, whereas is.whole(4/3) would be false. At the moment I am using is.whole <- function(a) { floor(a)==a } which is OK for real numbers, but not for complex ones (a+bi would be a whole number if both a

Hi, I need to parse a data file (output of a measuring device) of the following format: BEGIN RECORD [first record data] RECORD [second record data] RECORD [third record data] END Line breaks can (and do ;-() occur anywhere. White space behaves very much like TeX, eg it is not important whether there are one or more spaces or linebreaks as long as there is one of them. It is a text file, not

Hi, I have noticed the following: > a <- array(1:4, c(2, 2)) > A <- array(1:4, c(2,2,2)) > A + a Error in A + a : non-conformable arrays It works with a matrix + a vector, why doesn't it work with arrays? Am I missing something? How would you do the above operation efficiently (ie I need to add a matrix to each "plane" of 3-dim array)? At the moment I am using

Hi, I am writing a collection of functions which I plan to share as a package later (when they are tested thoroughly), so I would like to do things "right" from the beginning... I encountered a minor question of style. Consider a function f <- function(a,b,x=NULL) { ## ... } if !is.null(x), f will use x to calculate the result, but if is.null(x), it will do something else not

Dear list, I'd like to use the function cut() on matrices, ie that when I apply it to a matrix, it would return a matrix of the same dimensions instead of a vector. I wonder if there is a better (more elegant) solution than matrix(cut(a, ...), ncol=ncol(a), nrow=nrow(a)) because I would like to use cut on both vectors and matrices and avoid testing whether a is a matrix. Thanks, Tamas

Dear List, I have a couple of (~200) 3x3 transition probability matrices (ie each defines a Markov chain). They are all estimated from the same underlying process, so it ie meaningful to take their elemetwise mean and standard deviation. [1] First question: supposing that they are given in a list l, how do I get their elementwise mean and standard deviation? Fortunately, the mean of trans. prob.

Hi, I wonder if it would make sense to make uniroot detect zeros at the endpoints, eg if f(lower)==0, return lower as the root, else if f(upper)==0, return upper as the root, else stop if f(upper)*f(lower) > 0 (currently it stops if >=), else proceed to the algorithm proper. Currently I am using a wrapper function to implement this, and I found it useful. But I didn't want to send a

The fact that as.integer(TRUE) is 1 (and that for FALSE, it gives zero) is a really nice feature, eg when constructing piecewise functions (for example, as in -x*(x<0)+x*(x>=0)) and for many other things. Since I haven't found a reference about this, I just wanted to ask whether this is officialy part of the language or just a side effect (ie I want to know whether it is here to stay

Hi, I am typesetting R code in TeX using the listings package. I have experimented with various settings for the text, but all look a bit ugly. This might be because I have no typographic experience ;-) I would really appreciate if people sent me the settings they use for the listings package (eg in the \usepackage line, or \lstset, I am thinking about choices for basicstyle, ... etc). I

Hi, I have sparse (tridiagonal) matrices, and I use the Matrix package for handling them. For certain computations, I need to either set the first row to zero, or double the last row. I find that neither operation preserves sparsity, eg > m <- Diagonal(5) > m 5 x 5 diagonal matrix of class "ddiMatrix" [,1] [,2] [,3] [,4] [,5] [1,] 1 . . . . [2,] . 1

I am an economist who decided it's high time that I learned some Bayesian statistics. I am following An Introduction to Modern Bayesian Econometrics by T. Lancaster. The book recommends using BUGS, but I wonder if there are any alternatives which are free software and fully integrated to R (which I have been using for more than two years for numerical computations.) I would like to learn

Hi, I have a dynamic programming problem with many state variables, let's call them l, n, m, etc. The transition probabilities are originally given in an array form, eg transtition[l,m,n,ll,mm,nn] give the probability of going from l,m,n to ll,mm,nn. However, the numerical solution is best handled when I "flatten" the L x M x N state space into a single one (call it S), ie a

Dear List, I am trying to become more familiar with Sweave at the moment, beacuse I am convinced that it will eventually make my life easier. However, I have not found anything relevant in the mail archives about the following problem. Both the article in R-News and the Sweave FAQ suggest that Emacs would be a great development environment for working with Sweave. So far, it doesn't seem to

Hi, I found some bottlenecks in my R code with Rprof. First I wanted to rewrite them in C, but a colleague keeps suggesting that I learn Fortran, so maybe this is the time to do it... I like to learn new languages and do it fairly quickly. I would appreciate the advice of others about these questions: 1) I hear bad things about Fortran. Sure, F77 looks archaic, but F90/95 seems nicer. Is it

Suppose I have A, an n x m matrix, each element is an integer (an index). I also have B, an n x l x m array. I need C, where C[n,m] = B[n, A[n, m], m] I am currently using loops, what would be the "R way" to do this? Another question: let A[n, m] <- argmax_l B[n, l, m] what would be the nicest way of doing this? Currently I am using max.col and a single loop, going though the

Hi, I am trying to find an elegant way to compute and store some frequently used matrices "on demand". The Matrix package already uses something like this for storing decompositions, but I don't know how to do it. The actual context is the following: A list has information about a basis of a B-spline space (nodes, order) and gridpoints at which the basis functions would be