[R] R-help

[R. Michael Weylandt]

Another way, which I believe will be a little more memory efficient
and time inefficient, though that might vary by machine, would be to
use replicate:

library(MASS)
set.seed(123)
m <- replicate(1000, coef(fitdistr(rweibull(50, 0.8, 2), "weibull")))
summary(t(m)) # Need to transpose here (or you could do it in the line
above, but it's already crowded)

I haven't tested my efficiency claims, but I'm pretty sure you gain on
the memory end because it runs each simulation sequentially and only
stores results, and you loose on the time end because you wind up
calling rweibull() 1000 times instead of once. If you are leaning
heavily on your memory bounds though, the time thing might be moot due
to paging effects.

Michael

On Fri, Jan 27, 2012 at 8:39 AM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> On Fri, Jan 27, 2012 at 6:35 AM, Christopher Kelvin
> <chris_kelvin2001 at yahoo.com> wrote:
>> Hello,
>> How can i do simulation with a weibull distribution after i have generated data with the distribution,
>> for example; if i generate x=rweibull(50,shape=0.8,scale=2) and i want to simulate this data 1000 times so that i can use it to estimate
>> the parameters.
>
> library(MASS)
> set.seed(123)
> n <- 1000
> k <- 50
> r <- matrix(rweibull(n*k, shape = 0.8, scale =2), k)
> m <- t(apply(r, 2, function(x) coef(fitdistr(x, "weibull"))))
> summary(m)
>
> Please use a meaningful subject on your posts to r-help and trim them
> so that they don't include the literally thousands of lines of garbage
> that were at the end of your post.
>
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