Please keep this on the r-help mailing list. AROONALOK PYNE <aroonalok.p...@gmail.com> writes:
> R version 3.0.2 (2013-09-25)
>
>
> Large value : 9999999
>
>
> I rerun the code as c(10000000) for which your machine works fine but
> my code still hangs on reaching b(). I am running it from Linux
> Terminal.
Might be memory allocation issue (hardware)? I have 1GB of memory. If I
am not mistaken, all the data is copied into different R threads when
using mclapply - so the memory requirement is much bigger.
Cheers,
Rainer
>
>
> On Thu, Jun 11, 2015 at 2:15 PM, Rainer M Krug <rai...@krugs.de> wrote:
>
>> AROONALOK PYNE <aroonalok.p...@gmail.com> writes:
>>
>> > Please check this code :
>> >
>> > library(parallel)
>> > workerFunc <- function(n) { return(n^2) }
>> > a <- function(){
>> > CurrentTime <- Sys.time()
>> > res <- lapply(values, workerFunc)
>> > TimeTaken <- Sys.time() - CurrentTime
>> > print(TimeTaken)
>> > }
>> > b <- function(){
>> > CurrentTime <- Sys.time()
>> > numWorkers <- detectCores()
>> > res <- mclapply(values, workerFunc, mc.cores = numWorkers-2)
>> > TimeTaken <- Sys.time() - CurrentTime
>> > print(TimeTaken)
>> > }
>> > c <- function(n){
>> > values <<- 1:n
>> > print("Evaluating a : ")
>> > a()
>> > print("Evaluating b : ")
>> > b()
>> > }
>> >
>> > For large values of n, the code calculates a() but the hangs indefinitely
>> > on reaching b(). How do I correct it ?
>> > I am using Ubuntu 14.04 and core i7 Processor
>>
>> Which version of R and what are "large values"?
>>
>> I just did the following successfully:
>>
>> ,----
>> | > c(100)
>> | [1] "Evaluating a : "
>> | Time difference of 0.0002059937 secs
>> | [1] "Evaluating b : "
>> | Time difference of 0.02037406 secs
>> | > c(1000)
>> | [1] "Evaluating a : "
>> | Time difference of 0.001929998 secs
>> | [1] "Evaluating b : "
>> | Time difference of 0.01943302 secs
>> | > c(1000000)
>> | [1] "Evaluating a : "
>> | Time difference of 1.822959 secs
>> | [1] "Evaluating b : "
>> | Time difference of 1.46111 secs
>> | > c(10000000)
>> | [1] "Evaluating a : "
>> | Time difference of 23.55863 secs
>> | [1] "Evaluating b : "
>> | Time difference of 15.90938 secs
>> | >
>> `----
>>
>> Cheers,
>>
>> Rainer
>> --
>> Rainer M. Krug
>> email: Rainer<at>krugs<dot>de
>> PGP: 0x0F52F982
>>
--
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology,
UCT), Dipl. Phys. (Germany)
Centre of Excellence for Invasion Biology
Stellenbosch University
South Africa
Tel : +33 - (0)9 53 10 27 44
Cell: +33 - (0)6 85 62 59 98
Fax : +33 - (0)9 58 10 27 44
Fax (D): +49 - (0)3 21 21 25 22 44
email: rai...@krugs.de
Skype: RMkrug
PGP: 0x0F52F982
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