similar to: numerical solution of functional equations (dynamic stochastic optimization)

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.

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 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

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

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

I'd like to specify strings spanning multiple lines (ie too long to fit in a single line without spoiling pretty-printed R code). I tried the following way: > a <- "multiple \ + lines" but > print(a) [1] "multiple \nlines" How could I avoid the extra linebreak ("\n")? Regards, Tamas Papp -- Tam?s K. Papp E-mail: tpapp at axelero.hu (preferred,

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

I would like a 3d plot of a matrix such that individual trapezoids that make up the surface are colored according to the z-value of that point (or preferably the midpoint of its four corners, or something similar). MS Excel has something like that. I know that persp can have an nx by ny matrix its "col" argument, I just don't know how to generate that matrix. To calculate the

I have a function that returns multiple elements in a list (for the sake of the example here, this will simply be a list of two elements, a and b, but it is actually five named elements). This functions computes these values in an iterative manner, and I would like to start with an empty list and append the list of return values to this list (so that they would remain lists). The Scheme code for

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 read the 2000 thread on a MetaPost device in R. If I understand correctly, the main problem with the concept is that R wants the device driver to give back information on the size of strings/labels. To the bet of my knowledge, MetaPost _does_ make it possible to measure the bounding box of text (see section 7.3: Measuring text in the MetaPost manual). For example, one could get the size of

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 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

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

Hi, Sometimes I want to "reset" the R interpreter (as if I quit and started it again, with everything starting from scratch). The main reason for this is when I expreriment with calculations, and later form them into general functions, sometimes I forget to include variables or reset some settings which I don't notice because they are already set. This causes problems during batch

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 the following problem. It has two parts. 1. I need to calculate the stationary probabilities of a Markov chain, eg if the transition matrix is P, I need x such that xP = x in other words, the left eigenvectors of P which have an eigenvalue of one. Currently I am using eigen(t(P)) and then pick out the vectors I need. However, this seems to be an overkill (I only need a single

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

After making E <- eigen( something ) I would like to extract those eigenvectors which have an eigenvalue of 1. If I had an isone() function, I would simply say E$vectors[,which(isone(E))] but the problem is that I have no such thing. I found all.equal, so I could test for all.equal(x, 1), but for complex numbers, I need to use something like all.equal(x, 1+0i), don't I? I tried

Hi, I want to draw rectangles with "rect" without borders, but with shading (ie setting density). ?rect says lty: line type for borders; defaults to '"solid"'. but if I set it to 0, the border disappears, but the shading also vanishes! But the above says that lty is the line type for BORDERS, and does not mention density at all -- how do I get around this?