Stephen Henderson Malarkey73
Malarkey73
/ R and Julia Vectorisation
Last active
January 1, 2016 05:09
A slightly different comparison of R and Julia vectorisation closer to what most R people mean when they say "vectorised". The code example is plucked from the Julia blog discussion on code optimisation. Surprisingly for this use case Julia devectorised (~=0.18 secs) is just a little better than Julia vectorised (~= 0.25 secs), which is a little…
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| This is sort of a reply to this post: | |
| http://www.johnmyleswhite.com/notebook/2013/12/22/the-relationship-between-vectorized-and-devectorized-code/ | |
| which arises from a a discussion of this | |
| http://julialang.org/blog/2013/09/fast-numeric/ | |
| So.... |
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| # vectorised function | |
| vectorised <- function(x, y) | |
| { | |
| r = exp(-abs(x-y)) | |
| return(r) | |
| } | |
| #devectorised function | |
| devectorised <- function(x,y) | |
| { |
Malarkey73
/ Julia Vectorisation
Created
December 23, 2013 14:00
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| # vectorised function from Julia blog | |
| function vectorised(x,y) | |
| r = exp(-abs(x-y)) | |
| return r | |
| end | |
| # recommended devectorised function | |
| function devectorised(x,y) | |
| r = similar(x) | |
| for i = 1:length(x) |