similar to: mclapply hanging occasionally on macos

sequoia, 15.2. R --vanilla : 4.4.2 (2024-10-31). I have the same basic setup on three macs: a macbook air, a mac pro m1, and a mac mini m4. The following code is running into a bug on the mac pro m1 and the mac mini, but works just fine on my macbook air. (of course, it doesn't do anything useful.) it's replicable! ``` $ R --vanilla > source("debug.R") ``` and (after

? Mon, 30 Dec 2024 19:16:11 -0800 Ivo Welch <ivo.welch at gmail.com> ?????: > useless.function <- function( ) { > y <- rnorm(3); x <- rnorm(3) > summary( lm( y ~ x )) ## useless > NULL > } > > run30 <- function(i) { > message("run30=", i) > useless.function() > } > > run30( 0 ) > message("many mc")

On Wed, 17 May 2023 13:55:59 +0000 akshay kulkarni <akshay_e4 at hotmail.com> wrote: > So that means mclapply should run properly, i.e output a try class > object and exit. But it didn't. Can you shed some light on why this > happened? What's your sessionInfo()? Are you using a GUI frontend? mclapply() relies on the fork() system call, which is tricky to get right in a

Dear Ivan, REgrets to reply this late... By "holding a lock", you mean a bug in the process right (I am not a computer science guy, excuse my naivete)? THanking you, Yours sincerely, AKSHAY M KULKARNI ________________________________ From: Ivan Krylov <krylov.r00t at gmail.com> Sent: Thursday, May 18, 2023 1:08 PM To: akshay kulkarni <akshay_e4 at

Dear Jeff, There was a problem in LYGH and lapply threw an error, but mclapply got stuck in an infinite loop. The doc for mclapply says that mclapply runs under try() with silent = TRUE. So that means mclapply should run properly, i.e output a try class object and exit. But it didn't. Can you shed some light on why this happened? THanking you, Yours sincerely, AKSHAY M

Hi, a few comments below. First, from my experience and troubleshooting similar reports from others, a returned NULL from parallel::mclapply() is often because the corresponding child process crashed/died. However, when this happens you should see a warning, e.g. > y <- parallel::mclapply(1:2, FUN = function(x) if (x == 2) quit("no") else x) Warning message: In

dear R experts---I am looking at a fairly uninformative error in my program: Error in mclapply(1:nrow(opts), solveme) : (converted from warning) all scheduled cores encountered errors in user code the doc on ?mclapply tells me that In addition, each process is running the job inside try(..., silent=TRUE) so if error occur they will be stored as try-error objects in the list. I looked up

Sorry, the code works perfectly fine for me in R even for 1e6 observations (but I was testing with R 4.0.0). Are you using some kind of GUI? Cheers, Simon > On 28/04/2020, at 8:11 PM, Shian Su <su.s at wehi.edu.au> wrote: > > Dear R-devel, > > I am experiencing issues with running GAM models using mclapply, it fails to return any values if the data input becomes large.

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

On Fri, 9 Jun 2023 18:01:44 +0000 akshay kulkarni <akshay_e4 at hotmail.com> wrote: > > LYG <- pbmclapply(LYGH,FUN = arfima,mc.cores = 2,mc.preschedule = > > FALSE) > | > | > 0%, ETA NA^ > > It just hangs. My questions from the last time still stand: 0) What is your

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

Dear R-devel, I am experiencing issues with running GAM models using mclapply, it fails to return any values if the data input becomes large. For example here the code runs fine with a df of 100 rows, but fails at 1000. library(mgcv) library(parallel) > df <- data.frame( + x = 1:100, + y = 1:100 + ) > > mclapply(1:2, function(i, df) { + fit <- gam(y ~ s(x, bs =

Hello, I spent a lot of a time on a weird bug, and I just managed to narrow it down. In parallel code (here with parallel::mclappy, but I got it doMC/multicore too), if the library(tcltk) is loaded, R hangs when trying to open a DB connection. I got the same behaviour on two different computers, one dual-core, and one 2 xeon quad-core. Here's the code: library(parallel) library(RSQLite)

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)

Dear R wizards--- I have a wrapper on mclapply() that makes it a little easier for me to do multiprocessing. (Posting this may make life easier for other googlers.) I pass a data frame, a vector that tells me what rows should be recomputed, and the function; and I get back a vector or matrix of answers. d <- data.frame( id=1:6, val=11:16 ) loc <- c(TRUE,TRUE,FALSE,TRUE,FALSE,TRUE)

Yes I am running on Rstudio 1.2.5033. I was also running this code without error on Ubuntu in Rstudio. Checking again on the terminal and it does indeed work fine even with large data.frames. Any idea as to what interaction between Rstudio and mclapply causes this? Thanks, Shian On 28 Apr 2020, at 7:29 pm, Simon Urbanek <simon.urbanek at R-project.org<mailto:simon.urbanek at

Thanks Henrik, That clears things up significantly. I did see the warning but failed to include it my initial email. It sounds like an RStudio issue, and it seems like that it?s quite intrinsic to how forks interact with RStudio. Given this code is eventually going to be a part of a package, should I expect it to fail mysteriously in RStudio for my users? Is the best solution here to migrate all

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 use of it. The goal for the current piece of code I?m working on is to bootstrap many

I've been using mclapply and have encountered situations where it gives errors or returns incorrect results. Here's a minimal example, which gives the error on R 2.15.2 on Mac and Linux: library(parallel) f <- function(x) NULL mclapply(1, f, mc.preschedule = FALSE, mc.cores = 1) # Error in sum(sapply(res, inherits, "try-error")) : # invalid 'type' (list) of argument

Regarding the following code, warning(sprintf(ngettext(has.errors, "scheduled core %s encountered error in user code, all values of the job will be affected", "scheduled cores %s encountered errors in user code, all values of the jobs will be affected"), paste(has.errors, collapse = ", ")), domain = NA) has.errors is a vector whose elements are the