[Rd] mcmapply Core Usage
nilsson.henric at gmail.com
Fri May 30 02:04:15 CEST 2014
Simon Urbanek skrev 2014-05-29 15:06:
> yes, that is a bug, now fixed.
Thanks for fixing it.
This problem was independently reported some time ago
(https://bugs.r-project.org/bugzilla/show_bug.cgi?id=15016) and I
believe that it can now be closed.
> On May 29, 2014, at 2:00 AM, Dario Strbenac <dstr7320 at uni.sydney.edu.au> wrote:
>> I have a minimal example that shows a problem I'm having with parallel processing.
>> mcmapply(function(x, y)
>> }, as.list(1:10), as.list(10:1), mc.cores = 16, SIMPLIFY = FALSE)
>> I see "Running" printed once every ten seconds. I read the documentation for mcmapply, but I don't understand why it wouldn't print all ten output statements almost at once, then wait for about ten seconds, then return to the prompt. Is it documented in another location ?
>> My problem is that I have a section of code that takes a long time, which I have replaced with Sys.sleep in the above example, but when I look at the output of top, I only see 1 CPU being used. The computer has 16 processors.
>> R version 3.1.0 (2014-04-10)
>> Platform: x86_64-pc-linux-gnu (64-bit)
>>  LC_CTYPE=en_AU.UTF-8 LC_NUMERIC=C
>>  LC_TIME=en_AU.UTF-8 LC_COLLATE=en_AU.UTF-8
>>  LC_MONETARY=en_AU.UTF-8 LC_MESSAGES=en_AU.UTF-8
>>  LC_PAPER=en_AU.UTF-8 LC_NAME=C
>>  LC_ADDRESS=C LC_TELEPHONE=C
>>  LC_MEASUREMENT=en_AU.UTF-8 LC_IDENTIFICATION=C
>> attached base packages:
>>  parallel stats graphics grDevices utils datasets methods
>>  base
>> loaded via a namespace (and not attached):
>>  tools_3.1.0
>> Dario Strbenac
>> PhD Student
>> University of Sydney
>> Camperdown NSW 2050
>> R-devel at r-project.org mailing list
> R-devel at r-project.org mailing list
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