I'm suspecting this is confusion about default behavior.
R automatically updates the random seed when random numbers are generated (or other random operations are performed). The original poster may have experienced systems where it is up to the user to change the seed. I'd suggest two rules of thumb when coming up against something in R that you aren't sure about: 1. If it is a mundane task, R probably takes care of it. 2. Experiment to see what happens. Of course you could read documentation, but no one does that. On 05/11/2011 00:59, R. Michael Weylandt wrote:
This might be more fundamental, but why do you feel the need to reset the seed each loop? There's nothing that suggests you need to... Michael On Fri, Nov 4, 2011 at 8:38 PM, Md Desa, Zairul Nor Deana Binti <znde...@ku.edu> wrote:Hello, all! I need help on these two problems: 1) If I want to randomly draw numbers from standard normal (or other distributions) in loops e.g.: ty=0; ks=0 for (i in 1:5) { set.seed(14537+i) k<-rnorm(1) ks[i]<-.3*k+.9 if (ty==0) { while ((ks<.2)||(ks>3)) { #set.seed(13237+i*100) k<-rnorm(1) ks[i]-.3*k+.9 } } } .... .... .... } Question: Here I draw initial a, then if the drawn initial a satisfied 2 conditions I redraw a. I set.seed(13237) in the first draw of a, should I set.seed() in the redraw part? 2) I also have more loops after this i loop that also draw from normal(0,1). I want to randomly draws from normal(0,1) for loop j (inside loop j I draw another random numbers from N(0,1)) My question: Should I or shouldn't I set seed again and again for each loop? Why or why not. I guess this problem concerned about setting seed as I want to have different number for each i. Thanks! Deana ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
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