[R] For Loop
murdoch@dunc@n @end|ng |rom gm@||@com
Sun Sep 23 22:10:57 CEST 2018
On 23/09/2018 4:00 PM, Wensui Liu wrote:
> Very insightful. Thanks, Duncan
> Based on your opinion, is there any benefit to use the parallelism in
> the corporate computing environment where the size of data is far more
> than million rows and there are multiple cores in the server.
I would say "try it and see". Sometimes it probably helps a lot,
sometimes it's probably detrimental.
P.S. I last worked in a corporate computing environment 40 years ago
when I was still wet behind the ears, so you'd probably want to ask
someone else. However, more recently I worked in an academic
environment where I learned to say "try it and see" in many different
ways. You just got the basic one today.
> Actually the practice of going concurrency or not is more related to my
> production tasks instead of something academic.
> Really appreciate your thoughts.
> On Sun, Sep 23, 2018 at 2:42 PM Duncan Murdoch <murdoch.duncan using gmail.com
> <mailto:murdoch.duncan using gmail.com>> wrote:
> On 23/09/2018 3:31 PM, Jeff Newmiller wrote:
> [lots of good stuff deleted]
> > Vectorize is
> > syntactic sugar with a performance penalty.
> [More deletions.]
> I would say Vectorize isn't just "syntactic sugar". When I use that
> term, I mean something that looks nice but is functionally equivalent.
> However, Vectorize() really does something useful: some functions
> outer()) take other functions as arguments, but they assume the
> is a vectorized function. If it is not, they fail, or generate garbage
> results. Vectorize() is designed to modify the interface to a function
> so it acts as if it is vectorized.
> The "performance penalty" part of your statement is true. It will
> generally save some computing cycles to write a new function using a
> loop instead of using Vectorize(). But that may waste some
> programmer time.
> Duncan Murdoch
> (writing as one of the authors of Vectorize())
> P.S. I'd give an example of syntactic sugar, but I don't want to bruise
> some other author's feelings :-).
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