search for: 12e6

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2005 May 02
2
RMySQL query: why result takes so much memory in R ?
...millions of records I want to import 3 fields only. The fields are specified as:id int(11), group char(15), measurement float(4,2). Why does this take > 1G RAM? I run R on suse linux, with 1G RAM and with the code below it even fills the whole 1G of swap. I just don''t understand how 12e6 * 3 can fill such a huge range of RAM? Thanks for clarification and potential solutions. ## my code library(RMySQL) drv <- dbDriver("MySQL") ch <- dbConnect(drv,dbname="testdb", user="root",password="mysql") testdb <- dbGetQuery(c...
2018 Feb 20
2
Take the maximum of every 12 columns
Ista, et. al: efficiency? (Note: I needed to correct my previous post: do.call() is required for pmax() over the data frame) > x <- data.frame(matrix(runif(12e6), ncol=12)) > system.time(r1 <- do.call(pmax,x)) user system elapsed 0.049 0.000 0.049 > identical(r1,r2) [1] FALSE > system.time(r2 <- apply(x,1,max)) user system elapsed 2.162 0.045 2.207 ## 150 times slower! > identical(r1,r2) [1] TRUE pmax() is there f...
2018 Feb 20
1
Take the maximum of every 12 columns
On Tue, Feb 20, 2018 at 11:58 AM, Bert Gunter <bgunter.4567 at gmail.com> wrote: > Ista, et. al: efficiency? > (Note: I needed to correct my previous post: do.call() is required for > pmax() over the data frame) > > > x <- data.frame(matrix(runif(12e6), ncol=12)) > > > system.time(r1 <- do.call(pmax,x)) > user system elapsed > 0.049 0.000 0.049 > > > identical(r1,r2) > [1] FALSE > > system.time(r2 <- apply(x,1,max)) > user system elapsed > 2.162 0.045 2.207 > > ## 150 times s...
2018 Feb 20
1
Take the maximum of every 12 columns
...ue, Feb 20, 2018 at 11:58 AM, Bert Gunter <bgunter.4567 at gmail.com> > wrote: > >> Ista, et. al: efficiency? >> (Note: I needed to correct my previous post: do.call() is required for >> pmax() over the data frame) >> >> > x <- data.frame(matrix(runif(12e6), ncol=12)) >> >> > system.time(r1 <- do.call(pmax,x)) >> user system elapsed >> 0.049 0.000 0.049 >> >> > identical(r1,r2) >> [1] FALSE >> > system.time(r2 <- apply(x,1,max)) >> user system elapsed >> 2.162...
2018 Feb 20
1
Take the maximum of every 12 columns
This is what I was looking for. Thank you everyone! Sincerely, Milu <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Mail priva di virus. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>