similar to: parallel computing with 'foreach'

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 R-List member, I have a problem when I'm trying to save two arrays from a foreach-loop. I'm also not sure whether this is possible or just my inexperience. However, this works perferctly fine with a for-loop. Here is an example code - any help is much appreciated!!: ############ n.vpn = 2 n.run= 3 # create to empty matrices sme = matrix(NA,4,n.vpn) test = matrix(NA,4,n.vpn) #

Some might have noticed that REvolution Computing released the doSMP package to the general public about a month and a half ago, which allows multiple cores to be accessed for parallel computation in R. Some of our physical habitat calculations were taking an extraordinary amount of time to complete and required over-weekend runs, which prompted our interest in this package. What follows

Hello! I have something like this: test1 <- data.frame(intx=c(4,3,1,1,2,2,3), status=c(1,1,1,0,1,1,0), x1=c(0,2,1,1,1,0,0), x2=c(1,1,0,0,2,2,0), sex=c(0,0,0,0,1,1,1)) and I can easily fit a cox model: library(survival) coxph(Surv(intx,status) ~ x1 + x2 + strata(sex),test1) However, I want to

Dear R-help, I am using R-3.3.2 on Windows 10. I teach on a course which has 4 computer practical sessions related to the development and validation of clinical prediction models. These are currently written for Stata and I am in the process of writing them for use in R too (as I far prefer R to Stata!) I notice that predictions made from a Cox model in Stata are based on un-centred variables,

foreach (or virtually anything you might use for concurrent programming) only really makes sense if the work the "clients" are doing is substantial enough to overwhelm the communication overhead. And there are many ways to accomplish the same task more or less efficiently (for example, doing blocks of tasks in chunks rather than passing each one as an individual job). But more to the

Hello, I am trying to run a small example with foreach, but I am having some problems. Here is the code: *library(doMC) registerDoMC() zappa = list() frank = list() foreach (i = 1:4) %dopar% { zappa[[i]] = kmeans (iris[-5],4) frank[[i]] = warnings() }* The code runs without error. However the zappa and frank will be empty lists. If I use regular *for *instead, the list will be filled up

Hi all, I'm currently working on updating an R package to run for loops in parallel to speed up computation time. I'm using the 'foreach' package with a foreach loop. When I run my code inside the loop, I get an error message that a number of the functions aren't recognized (even though the functions have been defined); if I call my R package inside the loop, everything runs

All, I am not understanding the scoping used in foreach when it is used inside a function. I keep getting "could not find function" errors for functions that are in memory when I try to use foreach within a function call. I have a simple example below. "testFun" is in memory and works when called by foreach directly, but when I place foreach in a function called

Hi, in R 2.12.1, R CMD check hangs when building a vignette that uses a foreach loop with the doMC parallel backend. This does not happen in R 2.13.1, nor if I use doSEQ instead of doMC. All versions of multicore, doMC and foreach are the same on both my R installations. Has anybody encountered a similar issue? Thank you. Renaud ### UNIVERSITY OF CAPE TOWN This e-mail is subject to the

Dear all, I generate data under IRT mdel. I conducted 1000 replications. When I run, some replication was not fit with my model. So, replications were fit model were less than 1000 replication. If I want its run until 1000 replicaions. How shouldI write functin. Thank you, Kamontip [[alternative HTML version deleted]]

Thanks for the reproducable example. I can confirm that it fails on my machine using survival 2-37.5, the next soon-to-be-released version, The issue is with NextMethod, and my assumption that the called routine inherited everything from the parent, including the environment chain. A simple test this AM showed me that the assumption is false. It might have been true for Splus. Working this

Hi can ANY body help me to programme this formula: c[lj] and c[l'j] are matrix A[j]^-1 is an invertible diagonal matrix g[ll']=i[ll'] - sum *#from j=1 to k#* c[lj]c[l'j]A[j]^-1 WHERE i[ll']= 1/n sum from i=1 to n z[il] z[il'] n,k,m are given. j=1...k, l,l'=1...m, it s complicate for me ; hope you can help me thank you a lot -- View this

Since the three posters agree (only) that there is a bug, I propose to file it as a bug, which is the least we can do now. There is more to it: the only other case of a change in the Reference Manual which I know of, is also about the weights option! This is in coxph. The Reference Manual version 3.0.0 (2013) says about coxph: " ... If weights is a vector of integers, then the estimated

OK. We have now three suggestions to repair the text: - remove the text - add "not" at the beginning of the text - add at the end of the text a warning; something like: "Note that in this case the standard estimates of the parameters are in general not correct, and hence also the t values and the p value. Also the number of degrees of freedom is not correct. (The parameter

Hello, I'd like to use package 'doSMP'. But I can only found source codes in the CRAN. I tried to build source code using 'r CMD build doSMP' in the source directory, the following error is shown: ERROR: dependencies 'foreach', 'iterators', 'revoIPC' are not available for pack age 'doSMP' So, i tried to install dependency packages. But I

Hi list, I was testing out the "doSMP" package from REvolutionR in my regular R2.11.0 installation and I got the following error message.? Well, one obvious thing is that R2.11.0 was built using "i386-pc-mingw32" which is different from what revoIPC used.? I could just use REvolutionR, but all my R peripherals were set up to work with the regular R2.11.0.? So, I really want

Hello dear list, I just noticed that: Package ‘doSMP’ was removed from the CRAN repository. http://cran.r-project.org/web/packages/doSMP/index.html Does any one know the reason for this? Is this a technical or a legal (e.g: license) issue? Thanks, Tal ----------------Contact Details:------------------------------------------------------- Contact me: Tal.Galili@gmail.com | 972-52-7275845

Hello, I am having trouple installing doSMP and revoIPC from: https://r-forge.r-project.org/R/?group_id=950 My Linux system: Linux 2.6.35-25-generic #44-Ubuntu SMP Fri Jan 21 17:40:44 UTC 2011 x86_64 GNU/Linux Ubuntu 10.10 \n \l I get this reply: costas at ELEPHANT:~/Downloads$ sudo R CMD INSTALL revoIPC_1.0-3.tar.gz * installing to library ?/home/costas/R/x86_64-pc-linux-gnu-library/2.11? *

Dear expeRts, is it possible to carry out calculations between different foreach() calls? As for nested loops, you want to carry out calcuations not depending on the inner loop only once and not for each iteration of the innermost loop. Cheers, Marius library(foreach) foreach(i=1:3) %:% foreach(j=1:2) %do% { i <- i+1 print(paste(i,j)) } foreach(i=1:3) %:% i