Hello,
Inline.
Às 16:43 de 12/12/21, akshay kulkarni escreveu:
dear members,
I am a stock trader based in INDIA using R for my
research. I have two questions:
1. I want to send the same function with different arguments to different
cores. This link in SO
https://stackoverflow.com/questions/25045998/send-function-calls-with-different-arguments-to-different-processors-in-r-using
2. gives the following solution:
library(parallel)
cl <- makeCluster(4)
clusterExport(cl, "foo")
cores <- seq_along(cl)
r <- clusterApply(cl[cores], cores, function(core) {
if (core == 1) {
foo(5, 4, 1/2, 3, "a")
} else if (core == 2) {
foo(5, 3, 1/3, 1, "b")
} else if (core == 3) {
foo(5, 4, 1/4, 1, "c")
} else if (core == 4) {
foo(5, 2, 1/5, 0, "d")
}})
My question is: what is the structure of the output "r" in the above code? I think it is a list
with r[[1]] = output of foo(5,4,1/2,3,"a"),r[[2]] = output of foo(5,1/3,1,"b")
and so on. AM I right?
Yes, you are right. Why don't you try and print r[[1]]?
Anyway, I would put the parameters in a list and pass them to the
function following the below lines.
library(parallel)
foo <- function(pars){
x <- pars$x
y <- pars$y
z <- pars$z
w <- pars$w
alpha <- pars$alpha
res <- (x + y)*z^w
list(result = res, message = alpha)
}
params <- list(
list(x=5, y=4, z=1/2, w=3, alpha="a"),
list(x=5, y=3, z=1/3, w=1, alpha="b"),
list(x=5, y=4, z=1/4, w=1, alpha="c"),
list(x=5, y=2, z=1/5, w=0, alpha="d")
)
cl <- makeCluster(4)
clusterExport(cl, "foo")
clusterExport(cl, "params")
cores <- seq_along(cl)
r <- clusterApply(cl[cores], cores, function(core) {
foo(params[[core]])
})
stopCluster(cl)
do.call(rbind.data.frame, r)
Hope this helps,
Rui Barradas
1.
I am using RSelenium to scrape a website. Javascript has a document.ready
function which ensures that any JS code is run only after the whole document is
*
loaded. Is there a similar function in RSelenium? Or will the execution of the
next expression takes place only after the whole page is loaded (with the
*
"navigate" method of RSelenium)?
Thanking you,
Yours sincerely,
AKSHAY M KULKARNI
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
