similar to: Many cores support in R (Multicore Package)

Quick question regarding multicore versions of mapply. Package 'multicore' provides a parallelized version of 'lapply', called 'mclapply'. I haven't found any parallelized versions of 'mapply', however (although one can use the lower level function 'parallel', it becomes harder to control the number of spawned processes etc). Is anyone aware of a

Dear all. I am using the mclapply function to split my code to the many cores my system has. It seems that is working fine. This is the parallel version of lcapply. The only problem that I seem to have is that the printf cannot print messages. The ideal to me is to have fro my function an output of the form Shadowlist<-mclapply(1:dimz, function(i) { print(sprintf('Creating the

The attached code produces corrupted pdfs (test2.pdf, test4.pdf and test5.pdf). The resulting pdf depends on how many cores are available on the machine. I don't see why there should be any difference between the pdfs (exept for the timestamp). Doing many operations involving mclapply can increase the size of the resulting pdf by ten times! Thank you for checking this. require(multicore)

I'm running r 2. on a mac running 10.6.4 and a dual-core macbook pro. I'm having a funny time with multicore. When I run it with 2 cores, mclapply, R borks with the following error. The process has forked and you cannot use this CoreFoundation functionality safely. You MUST exec(). Break on __THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC__()

Dear R developers, with the inclusion of the package "parallel" in the upcoming release of R, users and package developers are likely to make increasing usage of parallelization features. In part, these features rely on forking the R process. As ?mcfork points out, fork()ing in a GUI process is typically a bad idea. In RKWard, we "only" seem to have problems with signals

I'm aiming to compare the workings of Rmpi and multicore on a duel processor quad core machine with 64 bit R-2.11.1 Kubuntu 10.4. It's impossible for me to get a small reproducable code segment to show what I mean, but if I show what works for mclapply, I'd hope it's possible to be shown what would be the equivalent way with mpi.apply. The function lr.gbm has variables trees,

Sir, I want to apply mclapply() function for my analysis. So, I have to install multicore package. But I can not install the package. >install.packages("multicore") It gives that package multicore is not available. Can you help me? Regards, Suman Dhara [[alternative HTML version deleted]]

Is there any reason to expect a problem ? i'm running this script on the cluster down the hall: module load R/2.11.0 R library(multicore) fxx<-function(ll) runif(1) mclapply(1:10,fxx) i get: Error in fork() : Unable to fork. less /proc/cpuinfo yields: processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Xeon(R) CPU

Hi all, I have R installed on a box, which is running on a machine with 16 core and Redhat - Linux. I am handling huge (size of dataset will be 5 GB) dataset. Lets assume that my data is in the form of structured (multiple) logs. I access the data by using all.files(). Since by default basic version of R utilizes single core, the processing of my analysis code is taking too much time. I got to

dear R readers---I thought I would post the following snippet of R code that makes by() like operations easier and faster on multicore machines for R novices and amateurs. I hope it helps some. YMMV. feel free to ignore. PS: I wish R had a POD-like documentation system for end users that are not writing full libraries. because it does not, I did not provide documentation ala '?mc.by'.

for the googleable r-help archives, I thought I would post what I wrote into my .Rprofile to automatically set some system information. the most relevant aspect is the determination of mc.cores. this is useful when users want to use the parallel package options(uname= system("uname", intern=TRUE)) options(os= if (getOption("uname")=="Darwin") "osx"

On 4 April 2019 at 17:28, ivo welch wrote: | The following program is whittled down from a much larger program that | always works on Intel, and always works on AMD's threadripper with | lapply but not mclappy. With mclapply on AMD, all processes go into | "suspend" mode and the program then hangs. This bug is replicable on an | AMD Ryzen Threadripper 2950X 16-Core Processor (128GB

dear r experts---Is there a multicore equivalent of by(), just like mclapply() is the multicore equivalent of lapply()? if not, is there a fast way to convert a data.table into a list based on a column that lapply and mclapply can consume? advice appreciated...as always. regards, /iaw ---- Ivo Welch (ivo.welch at gmail.com)

I have matrices as below: a <- matrix(c(1:10, 11, 12), 3,4) aa <- data.frame(a) b <- matrix(c(10:20, 21), 4,3) bb <- data.frame(b) ... and many more matrices. st = list(aa,bb, ..... ) mclapply(st, FUN, mc.cores=6); #this function apply the function to the elements of the list 'aa', 'bb'...etc FUN = function(st) { Is there a way/function to know the index of

This is a 'rather than re-invent the wheel' post. Has anyone out there re-written combn so that it can be parallelized - with multicore, snow, or otherwise? I have a job that requires large numbers of combinations, and rather than get all of the index values, then crank it through mclapply, I was wondering if there was a way to just do this natively within a function. Just curious.

On Tue, Apr 28, 2020 at 9:00 PM Shian Su <su.s at wehi.edu.au> wrote: > > Thanks Simon, > > I will take note of the sensible default for core usage. I?m trying to achieve small scale parallelism, where tasks take 1-5 seconds and make fuller use of consumer hardware. Its not a HPC-worthy computation but even laptops these days come with 4 cores and I don?t see a reason to not make

The following program is whittled down from a much larger program that always works on Intel, and always works on AMD's threadripper with lapply but not mclappy. With mclapply on AMD, all processes go into "suspend" mode and the program then hangs. This bug is replicable on an AMD Ryzen Threadripper 2950X 16-Core Processor (128GB RAM), running latest ubuntu 18.04. The R version

Do NOT use mcparallel() in packages except as a non-default option that user can set for the reasons Henrik explained. Multicore is intended for HPC applications that need to use many cores for computing-heavy jobs, but it does not play well with RStudio and more importantly you don't know the resource available so only the user can tell you when it's safe to use. Multi-core machines are

Dear all, I am using my code the vgram.matrix of packets fields. I have around 500 matrices that I need to pass inside that function and then plot those results. Even though my system has 16 cores is quite clear that I am only using one of those. Would it be able to skip these 500 "tasks" to the 16 cores, with each processor having around 4 matrices to process? What would you suggest

Dear all, I am trying to multiply three different matrices and each matrice is of size 16384,16384 the normal %*% multiplciation operator has not finished one day now. As I am running a system with many cores (and it seems that R is using only one of those) I would like to write fast a brief function that converts the typical for loops of a matrix multiplication to a set of lapply sets (mclapply