Re: [R] AR Simulation with non-normal innovations - Correct

2009-11-03 Thread Ricardo Gonçalves Silva
Thanks Andreas.
This is just the start point I was needing.

Best,

Rick


From: Andreas Hary 
Sent: Tuesday, November 03, 2009 7:19 AM
To: Ricardo Gonçalves Silva 
Subject: Re: [R] AR Simulation with non-normal innovations - Correct


Have a look at function arima.sim. It allows you to specify a random number 
generator, so you could try something like the following:

arModel - list(ar = 0, ma = 0, order = c(0, 1, 0))
tGarchGen - function(a, b, c) {
  # your stuff here, must return a vector of random deviates
}
arima.sim(arModel, n = 100, rand.gen = tGarchGen)

If you would like to generate a bunch of series, say 200, all at once try

mySeries - replicate(200, arima.sim(arModel, n = 100, rand.gen = tGarchGen))


HTH,

Andreas






2009/11/2 Ricardo Gonçalves Silva ricard...@terra.com.br

  Dear Users,

  I would like to simulate an AR(1) (y_t=ct1+y_t-1+e_t) model in R where the 
innovations are supposed to follow a t-GARCH(1,1) proccess.

  By t-GARCH I want to mean that:

  e_t=n_t*sqrt(h_t) and
  h_t=ct2+a*(e_t)^2+b*h_t-1.

  where n_t is a random variable with t-Student distribution.

  If someone could give some guidelines, I can going developing the model.
  I did it in matlab, but the loops are very slowly, so I would like to try R.

  Thanks in advance,

  Rick
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[R] AR Simulation with non-normal innovations - Correct

2009-11-02 Thread Ricardo Gonçalves Silva
Dear Users,

I would like to simulate an AR(1) (y_t=ct1+y_t-1+e_t) model in R where the 
innovations are supposed to follow a t-GARCH(1,1) proccess. 

By t-GARCH I want to mean that:

e_t=n_t*sqrt(h_t) and
h_t=ct2+a*(e_t)^2+b*h_t-1.

where n_t is a random variable with t-Student distribution.

If someone could give some guidelines, I can going developing the model.
I did it in matlab, but the loops are very slowly, so I would like to try R.

Thanks in advance,

Rick
[[alternative HTML version deleted]]

__
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.