similar to: Wired behavior of a 2-by-2 matrix indicies

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 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 have two small questions confused me recently. Now assume I have a matrix "a", like this, > a <- matrix(1:6, 2, 3) > a [,1] [,2] [,3] [1,] 1 3 5 [2,] 2 4 6 I sometimes need each row of "a" raised to a different exponent. So I do a trick like this, > a^c(2, 3) [,1] [,2] [,3] [1,] 1 9 25 [2,] 8 64 216 My first

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

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

Dear R, Usually when I want to read pdf help for R functions under Linux, I do the following steps > help("par",help_type="pdf") > system(paste(getOption("pdfviewer"),"par.pdf")) which works well. First question, can I let "help" to save the pdf file to a different place other than current working directory? Now I want to write a small

Dear R, I have two R instances running at the same time, say instance A and instance B. Is there a simpler way to pass the data in A to B? More precise, I have a stupid example: In instance A, I am running a function "test1" test1 <- function (x1) { x2 <- sin(x1) return(x2) } In instance B, another function "test2" test2 <- function (x2) { x3 <-

Dear R-helpers, I intend to upgrade R in Mac OS with updated R version and updated Mac OS version. I think my Mac notebook is produced with Mac x86_64, darwin9.8.0. I have updated my Mac OS to Mac OS X version 10.6.5. But, when I installed R 2.12.1, the "version" function still gave me information that R is based on old Mac OS. I need to know how can I update R to let it to fit for

On 07/17/2013 04:15 PM, Gao feng wrote: > On 07/16/2013 01:29 PM, Guan Qiang wrote: >> 于 2013/7/15 17:32, Gao feng 写道: >>> On 07/15/2013 05:18 PM, hzguanqiang wrote: >>>> Hi, Gao Feng >>>> >>>> I've tried what you said, but still exists the problem: >>>> >>>> ubuntu@lxc:~$ vir attach-disk instance-0000002c