search for: foreach

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(...

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 pl...

Hi all, Within a foreach loop with doSNOW, we cant call functions which come from the non-default package. We need to load(require/library) the package once more within the foreach loop. Anyone knows why would happen like this? Is it caused by the snow package and something happened when "snow" parallelize the jo...

...| 2 libswfdec/swfdec_as_initialize.as | 4 + libswfdec/swfdec_as_initialize.h | 58 +++++++++++++++------------- libswfdec/swfdec_as_interpret.c | 44 +++++++++++++++++---- test/trace/Makefile.am | 9 ++++ test/trace/foreach-proto-simple-5.swf |binary test/trace/foreach-proto-simple-5.swf.trace | 4 + test/trace/foreach-proto-simple-6.swf |binary test/trace/foreach-proto-simple-6.swf.trace | 4 + test/trace/foreach-proto-simple-7.swf |binary test/trace/foreach-proto-simple-7.swf.trace | 4...

I know this is not a revolution support forum, but as anyone noticed the following? I have a foreach loop to generate random samples. If I run the exact code below in normal r (2.14.1) it works as expected, but if I run it from revolution 4.2.0 each loop returns the same numbers. The only way I can get revolution to give different numbers is using 1 instead of 8 in registerDoSNOW(makeCluster(8, t...

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...

Hi all, I would like to parallelize some R code and would like to use the 'foreach' package with a foreach loop. However, whenever I call a function from an enabled package outside of MASS, I get an error message that a number of the functions aren't recognized (even though the functions should be defined). For example: library(foreach) library(doSMP) library(survival)...

Hi! I'm a recent convert from Stata, so forgive my ignorance. In Stata, I can write foreach loops (example below) foreach var of varlist p1-p14 { foreach y of varlist p15-p269 { reg `var' `y' } } It's looping p1-p15, p1-p16...., p1-p269, p2-p15, p2-p16,... p2-p269,... variable pairs. How can I write something similar in R? I 'tried' understanding th...

I started to look at ways to improve times of certain very parallel tasks and thought that foreach should be a valid candidate to do the job. So, i opened foreach tutorial by Steve Weston and started timing examples from it. First example from tutorial is  >system.time(for(i in 1:100000) sqrt(i))    user  system elapsed     0.06    0.00    0.06  > system.time(foreach(i=1:100000) %do% sq...

I recently learned about the bigmemory and foreach packages and am trying to use them to help me create a very large matrix. Without those packages, I can create the type of matrix that I want with 10 columns and 5e6 rows. I would like to be able to scale up to 5e9 rows, or more, if possible. I have created a simplified example of what I'...

Dear all, Just wondering if someone could help me out converting my code from a for() loop into a foreach() loop or using one of the apply() function. I have a very large dataset and so I'm hoping to make use of a parallel backend to speed up the processing time. I'm having trouble getting selecting three variables in the dataset to use in the foreach() loops. My for() loop code is: library(fo...

...s takes a lot of time and I'd like to do this in parallel, if possible. If it's the disk reading speed that is the bottleneck I guess I should not expect an improvement, but perhaps it's the processor. So I want to try this out. I'm working on windows 7 with R 2.15.1 and the latest foreach and doSNOW packages. See sessionInfo() below. Thanks in advance for any inputs! # With lapply it works (i.e. each .tar.gz file is decompressed into several directories with the files of interest inside) lapply(tar.files.vector, FUN=untar) # It also works with foreach in serial mode: foreach(i=1:...

Hi, just during these vacation days, I'm trying to approach with multicore package and I have some troubles with foreach. ex. foreach(.combine=c, ii=1:200, jj=1:500) %dopar% makefunction[ii,jj] Command seem to work but if I see ii and jj value at the and of cycle, they are both 200 instead than ii=200 and jj=500. Why?? Can someone help me? Thank you in advance. Max -- View this message in context: http://r.7...

I'm trying to find examples of the foreach pattern being used in tablegen files. The problem I am trying to solve is to simplify the amount of tablegen code I have to produce because each operand of an instruction can be a register or a literal. So for binary, we have 4 instructions, ternary, 8, and quaternary 16 combinations. Instead of w...

Hi there! I have become a big fan of the 'foreach' package allowing me to do a lot of stuff in parallel. For example, evaluating the function f on all elements in a vector x is easily accomplished: foreach(i=1:length(x),.combine=c) %dopar% f(x[i]) Here the .combine=c option tells foreach to combine output using the c()-function. That is, to...

...with pretty disappointing results. Here is my simple example: A <- 100000 randvalues <- abs(rnorm(A)) minfn <- function( x, i ) { log(abs(x))+x^3+i/A+randvalues[i] } ?## an arbitrary function ARGV <- commandArgs(trailingOnly=TRUE) if (ARGV[1] == "do-onecore") { ?library(foreach) ?discard <- foreach(i = 1:A) %do% uniroot( minfn, c(1e-20,9e20), i ) } else if (ARGV[1] == "do-multicore") { ?library(doMC) ?registerDoMC() ?cat("You have", getDoParWorkers(), "cores\n") ?discard <- foreach(i = 1:A) %dopar% uniroot( minfn, c(1e-20,9e20...

Hi all, Sometimes I'll find myself "ctrl-c"-ing like a madman to kill some code that's parallelized via foreach/doMC when I realized that I just set my cpu off to do something boneheaded, and it will keep doing that thing for a while. In these situations, since I interrupted its normal execution, foreach/doMC doesn't "clean up" after itself by killing the processes that were spawned. Furthermo...

Hi list, My attention was drawn to the foreach package by recent posts...I decided to have a look... I'm using R.2.9.1 on Windows, I have downloaded the foreach package today (v 1.2.1), together with iterators (v. 1.0.1) and codetools (v.0.2-2). Full of hope I try the most simple thing of all out of the package vignette : > x <- f...

Hi, I am trying to parallel computing with foreach function, but not able to get the result. I know that in parallel processing, all result is collected in list format, but I am not able to get input there. Any help is really appreciated. esf.m <-foreach (i = 1:n.s, .combine=rbind) %dopar% { EV <- as.data.frame(eig$vectors[,1:n.candid[i]...

Hi useRs, I am running a foreach loop and hoped to get a small message when it hits a multiple of 1000, but it does not work. p <- foreach(i=1:10000, .combine='c') %dopar% { if(i%%1000==0) print(i) sqrt(i) } What is the proper way to do it. Thanks everybody. Stephen B [[alte...