Ways to speed up R code?

RSiteSearch("speed up R code")
== search for a page having the words (speed, up, R, and code)
surely R is found everywhere.
Although there are some useful archives, many of them are not.
Furthermore, I need a general instruction instead of pieces (e.g.
Patrick's book and Duncan's rules)

If I use "speed up R code" as a phrase, then only one not-very-useful hit.

Thanks,
Xiaohua



On 10/18/05, Thomas Sch??nhoff <tschoenhoff at gmail.com> wrote:

Hello,


2005/10/18, ecoinfo <ecoinformatics at gmail.com>:

Hi R-users:

Yesterday I ran a R code for 9 hours and it did not show any sign to
stop. Then I interrupted it and found it had completed 82.5%.

This morning I decided to wait for another 11 hours to see what will
happen. Wait a minute, I heard that transforming data.frame to matrix
will make R code faster. Then I made the modification in my R code.
Oooh, the new code finished within 30 minutes!!

Are there any other tips to speed up R program? Or someone could
indicate me some documents or websites on R code optimization?

#OS: Win XP, CPU: Pentium IV, 3.20G, Memory: 1G
#for() loop: 1000*1616*3*41, 3 data.frames (dim = c(1616,5), c(1616),
c(1616) respectively)

RSiteSearch("speed up R code") gives 346 hits, so this problem has
been discussed on this list some time before. Maybe something worth to
pay attention to?


regards
Thomas