[R] any other fast method for median calculation

[roger koenker]

There is a slightly faster algorithm in my quantreg package, see  
kuantile()
but this is only significant when sample sizes are very large.  In  
your case
you really need a wrapper that keeps the loop over columns within some
lower level language.

url:    www.econ.uiuc.edu/~roger            Roger Koenker
email    rkoenker at uiuc.edu            Department of Economics
vox:     217-333-4558                University of Illinois
fax:       217-244-6678                Champaign, IL 61820



On Apr 13, 2009, at 11:29 PM, Zheng, Xin (NIH) [C] wrote:

> Hi there,
>
> I got a data frame with more than 200k columns. How could I get  
> median of each column fast? mapply is the fastest function I know  
> for that, it's not yet satisfied though.
>
> It seems function "median" in R calculates median by "sort" and  
> "mean". I am wondering if there is another function with better  
> algorithm.
>
> Any hint?
>
> Thanks,
>
> Xin Zheng
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