[Rd] R as a scripting engine

[Simon Urbanek]

Oh, well, now that the post count is growing I guess I have to  
respond ;).

On Jan 11, 2009, at 15:50 , Dirk Eddelbuettel wrote:

>
> On 11 January 2009 at 20:18, Prof Brian Ripley wrote:
> | Those of you tracking R development will have noticed that we are
> | moving towards using R as a scripting engine.
> [...]
> | Reasons:
> |
> | - it is platform-independent and needs no other tools installed.
> [...]
> | - it is fast.
> [...]
>
> Indeed.  I really like working with r scripts.
>
> And littler by Horner and Eddelbuettel is faster than Rscript -- see  
> eg the
> scripts tests/timing.sh and tests/timing2.sh in the SVN archive /  
> littler
> tarballs (and the results below for illustration).
>

Well, if we enter that territory then rcmd from Rserve is much faster  
than littler:

  --- GNU bc doing the addition 10 times
real	0m0.029s
user	0m0.009s
sys	0m0.028s

  --- rcmd doing the addition 10 times
real	0m0.090s
user	0m0.010s
sys	0m0.022s

  --- our r doing the addition 10 times
real	0m0.294s
user	0m0.199s
sys	0m0.091s

  --- GNU R's Rscript doing the addition 10 times
real	0m1.626s
user	0m1.241s
sys	0m0.357s

  --- GNU R doing the addition 10 times
real	0m2.883s
user	0m2.424s
sys	0m0.426s

(littler and timig.sh script from http://littler.googlecode.com/svn/trunk 
  with loopRcmd added)


Yes, the comparison is unfair, but that applies to littler and Rscript  
as well. Once you start making direct comparisons the story is a bit  
different:

  --- our r doing the addition 10 times
real	0m0.297s
user	0m0.200s
sys	0m0.091s

  --- GNU R's Rscript doing the addition 10 times
real	0m0.390s
user	0m0.219s
sys	0m0.163s

(Rscript is now run with R_DEFAULT_PACKAGES=NULL since that is what  
littler really does).

.. and for timing2.sh (again, comparing Rcmd is technically a bit  
unfair, but the net effect for the user is good):

  --- rcmd calling summary() 20 times
real	0m0.439s
user	0m0.019s
sys	0m0.045s

  --- our r calling summary() 20 times
real	0m2.619s
user	0m2.089s
sys	0m0.476s

  --- GNU R's Rscript calling summary() 20 times
real	0m2.435s
user	0m1.793s
sys	0m0.590s

  --- GNU R calling summary() 20 times
real	0m5.789s
user	0m4.892s
sys	0m0.829s

so in fact Rscript is here faster than littleR!

(R 2.8.1 32-bit, Mac OS X 10.5.6, bash shell (due to echo bug), Quad  
2.66GHz Xeon, littler from SVN, rcmd from SVN, Rserve 0.5-2)


> We should still appreciate it you could finally acknowledge  
> existence of littler it in the R / Rscript documentation.   You are  
> not doing users any service by pretending it doesn't exist.
>

I don't think anyone is pretending anything. If users want littler  
specifically, they will find it, but I don't see why it should have  
anything to do with the R documentation - it's not part of R ...

Cheers,
S

PS: No, I'm not advertising Rserve here - it has its own place, but I  
wouldn't really use it for running random scripts. I have added it to  
the mix just to show that there is always a tradeoff, so it's  
important to know what is compared in benchmarks...


> That said, we are not (yet ?) building r for Windows, and I  
> appreciate that Rscript is available there.  Maintenance and use of  
> R will be easier with a consistent set of tools.  This is a good move.
>
> Dirk
>
>
> edd at ron:~/svn/littler/tests> ./timing.sh
>
> --- GNU bc doing the addition 10 times
> real    0m0.028s
> user    0m0.004s
> sys     0m0.012s
>
> --- our r doing the addition 10 times
> real    0m0.400s
> user    0m0.308s
> sys     0m0.052s
>
> --- GNU R's Rscript doing the addition 10 times
> real    0m2.077s
> user    0m1.832s
> sys     0m0.204s
>
> --- GNU R doing the addition 10 times
> real    0m3.974s
> user    0m3.728s
> sys     0m0.228s
> edd at ron:~/svn/littler/tests> ./timing2.sh
>
> --- our r calling summary() 20 times
> real    0m3.261s
> user    0m2.976s
> sys     0m0.240s
>
> --- GNU R's Rscript calling summary() 20 times
> real    0m4.164s
> user    0m3.624s
> sys     0m0.548s
>
> --- GNU R calling summary() 20 times
> real    0m8.087s
> user    0m7.552s
> sys     0m0.492s
> edd at ron:~/svn/littler/tests>
>
>
> -- 
> Three out of two people have difficulties with fractions.
>
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