Greg Snow wrote:
Try adding a version that uses sort with the partial argument, that should be
faster than regular sort (for long enough test vectors) and possibly faster
than the max solutions when finding more than just the largest 2.
I find the documentation for the partial argument in sor
e 04, 2009 2:18 AM
> To: r-help@r-project.org
> Subject: [R] Fast way of finding top-n values of a long vector
>
> If x is a (long) vector and n << length(x), what is a fast way of
> finding the top-n values of x?
>
> Some suggestions (calculating the ratio of the two t
On Thu, Jun 4, 2009 at 9:18 AM, Allan Engelhardt wrote:
> I want to apply this code to a few tens of thousands of vectors so speed
> does matter. In C or similar I would of course calculate the result with a
> single pass through x, and not with three passes as in 'max2'.
>
So why not code it
If x is a (long) vector and n << length(x), what is a fast way of
finding the top-n values of x?
Some suggestions (calculating the ratio of the two top values):
library("rbenchmark")
set.seed(1); x <- runif(1e6, max=1e7); x[1] <- NA;
benchmark(
replications=20,
columns=c("test","elapsed"),
ord
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