Hi: Use arima.sim because when you have recursive relationships like that, there's no way to not loop. If arima.sim doesn't allow for the trend piece (0.1*t ), then you can do that part seperately using cumsum(0.1*(1:t)) and then add it back in to what arima.sim gives you. I don't remember if arima.sim allows for a trend. It might.
Mark On Mon, Jun 25, 2012 at 8:39 AM, Kathie <kathryn.lord2...@gmail.com> wrote: > Dear R users, > > I'd like to compute X like below. > > X_{i,t} = 0.1*t + 2*X_{i,t-1} + W_{i,t} > > where W_{i,t} are from Uniform(0,2) and X_{i,0} = 1+5*W_{i,0} > > Of course, I can do this with "for" statement, but I don't think it's good > idea because "i" and "t" are too big. > > So, my question is that > > Is there any better idea to avoid "for" statement for this problem? > > Thank you in advance. > > Kathie > > -- > View this message in context: > http://r.789695.n4.nabble.com/do-call-or-something-instead-of-for-tp4634421.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > [[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.