similar to: a^c(1:3)

Dear R, I have a simple question concerning with a special case of spare matrix multiplications. Say A is a 200-by-10000 dense matrix. B is a 10000-by-10000 block- diagonal matrix, and each diagonal block B_i is 100-by-100. The usual way I did A%*%B will take about 30 seconds which is to time consuming because I have to do this thousands of times. I also tried to partition A into 100 small blocks

Dear all, Why does not the three-dot accept arguments from the parent environment? I am just confused with this error, can someone give me a hint? > rm(list=ls()) > testFun <- function(a, ...) + { + if(a){ + print(a) + }else + { + print(b) + } + } > > myTask <- function(a) + { + b <- 3 + testFun(a, b = b) + } >

Dear R, Is there an efficient way to make a list that each element is from the corresponding column of a matrix. For example, if I have a matrix "a" > a <- matrix(1:10, 5, 2) > a [,1] [,2] [1,] 1 6 [2,] 2 7 [3,] 3 8 [4,] 4 9 [5,] 5 10 I would like to have a list "b" like this > b <- list(a[, 1], a[, 2]) > b [[1]] [1] 1 2 3

Dear R, I have a silly question concerns with *apply. Say I have a list called A, A <- list(a = array(1:20, c(2, 2, 5)), b = array(1:30, c(2, 3, 5))) I wish to calculate the mean of A$a, and A$b w.r.t. their third dimension so I did lapply(A,apply,c(1,2),mean) Now if I still wish to do the above task but take away some burn-in, e.g. do not take A$a[,,1:2],and A$b[,,1:2] into account.

Dear R, Why rm(list<-ls()) gives an error but rm(list=ls()) not?. I remember the operator ‘<-’ can be used anywhere... Thanks! Feng -- Feng Li Department of Statistics Stockholm University 106 91 Stockholm, Sweden http://feng.li/ [[alternative HTML version deleted]]

Dear R, How can I disable using "enter" key to exit the browser() in debug mode? I would love to have this option because it is so annoying to jump out of the debugging mode unexpectedly when I don't want to. I guess some of us have encouraged at least one of these situations, 1, Accidentally pressed the enter key within the browser. 2, Copy and paste a piece of debugging code

Dear R, I am looking for R-package related to INARMA (Integer-valued ARMA). Can anyone give me some information? I did not get information from task view. Many thanks. Feng -- Feng Li Department of Statistics Stockholm University 106 91 Stockholm, Sweden http://feng.li/ [[alternative HTML version deleted]]

Dear R, I rare use the standard R-gui on Windows. Yesterday I tried the latest stable release on Windows 7 and XP and found one thing interesting. Assume currently I am running R code, say > example(plot) Then I click the "close window" button on the R main window. R asks me to save workspace image or not. Then I click "cancel". I suspect that my program

Dear R, Can't I cluster a dataset into k clusters where k is exactly the number of observations? I have version 12.2 installed. See this example > a <- matrix(1:100, 20) > kmeans(a, 20) Error: number of cluster centres must lie between 1 and nrow(x) This is a bit ad-hoc but I known R from version 2.12 allows number of clusters to be one. So I guess allowing number of clusters to be

Dear R, I have a covariates matrix with 10 observations, e.g. > X <- matrix(rnorm(50), 10, 5) > X [,1] [,2] [,3] [,4] [,5] [1,] 0.24857135 0.30880745 -1.44118657 1.10229027 1.0526010 [2,] 1.24316806 0.36275370 -0.40096866 -0.24387888 -1.5324384 [3,] -0.33504014 0.42996246 0.03902479 -0.84778875 -2.4754644 [4,] 0.06710229 1.01950917

Dear R, If I have remembered correctly, a square matrix is singular if and only if its determinant is zero. I am a bit confused by the following code error. Can someone give me a hint? > a <- matrix(c(1e20,1e2,1e3,1e3),2) > det(a) [1] 1e+23 > solve(a) Error in solve.default(a) : system is computationally singular: reciprocal condition number = 1e-17 Thanks in advance! Feng --

Dear R, I have a vector, say a = c(1,2,4,5,6,8). Can I generate a vector or array (2-by-3-by-3) of this form c(1,2,1,2,1,2,4,5,4,5,4,5,6,8,6,8,6,8), in which every two elements in "a" have been repeated twice? I am to stupid today and could not figure this simple question out... Many many thanks! Feng -- Feng Li Department of Statistics Stockholm University 106 91 Stockholm,

Dear R, I found a very wired behavior for a 2-by-2 matrix, see this example > A <- matrix(1:4, 2) > idx4A <- matrix(1:4, 2) > A[idx4A] Error in A[idx4A] : subscript out of bounds But other matrices are fine, > B <- matrix(1:9, 3) > idx4B <- matrix(1:9, 3) > B[idx4B] [1] 1 2 3 4 5 6 7 8 9 I can reproduce this for both 32bit windows and 64bit linux with R 2.12.1

Dear R, I have two questions: 1, Why both R and Matlab give 0*Inf==NaN? To my knowledge, it should be zero mathematically. Am I right? 2, I need to calculate e.g. exp(a)/(exp(b)+c), where both a and b are very large numbers (>>1000, e.g a=1000, b=1007, and c=5). R gives me NaN when I use the following command: > exp(1000)/(exp(1007)+5) [1] NaN I am pretty sure this should be close to

Things are going along well, but there is one remaining area of confusion...."units". I understand exponents now...it's basically how you pass decimal values. That's easy enough. But "units"....in other words, I have a voltage I want to put in a report. If I include in the report descriptor the fact that it is actually a voltage, with units of "volts",

I am having difficulty with the calculation of the power law exponent for set of nodes within a graph. Specifically, I am interested in the distribution of in-degree and out-degree among communities of web pages where the web pages are the nodes of the graph and the hyperlinks the edges. According to the literature, the distribution of incoming and outgoing links obeys a power law distribution

The real weird thing is I wrote "weird" and it comes out "wired"... The background is that I did a lot of sparse matrices calculations. Therefore need some indices tweaks, e.g subtract a block from a big matrix. Then I just create an indicies matrix and use it directly as a vector since a matrix is just a vector with dimensions attributed in R. I know I can convert them to a

Dear list members, this is not an R question and forgive me for using the list for irrelevant questions, but this is the only place I know where I can find some good statisticians and I need an expert opinion. There is this power law kinetic model of the form: M=kt^n where t is the time, M is the fraction of drug released, k is the rate constant and n is an exponent related to the mechanism of

Dear all, First I would like to thank the ESS people's all the hard work. I am watching the project closely and witnessing the improvements day by day. Besides I found a strange situation using `ess-tracebug'. Please tell me if I am wrong or this is a bug. Start Emacs with "emacs -Q" and load ESS and enable ess-tracebug. Create a file named `testFun1.R' with the

Hi, I'm drawing a very simple plot with both axes logarithmic (default base 10). Example: vec=c(1,10,100,1000,10000,100000,1000000,10000000) plot(vec,vec,log="xy") The axes on the plot now show the technical notation like 1E+3 but I would prefer to have it the notation 10 ^3 i.e. with the exponent here 3 superscript (raised). Any help very much appreciated! Best Regards Tom --