On 12-11-12 02:05 PM, Mark Leeds wrote: > Hi: Not sure if totally relevant because I didn't read it but it might > help or atleast > be of interest. > > http://journal.r-project.org/archive/2010-1/RJournal_2010-1_Wilhelm+Manjunath.pdf
This definitely looks relevant. The critical question will be how large a sample the original questioner needs to generate. If it's not too big, then they can just construct their own correlation matrix, and go from there. Ben > > > On Mon, Nov 12, 2012 at 12:15 PM, Ben Bolker <bbol...@gmail.com > <mailto:bbol...@gmail.com>> wrote: > > Zhenglei Gao <zhenglei.gao <at> bayer.com <http://bayer.com>> writes: > > > I have asked the same question on stackoverflow but did not get a > > satisfying answer. > > > I am trying to simulate a lognormal spatial random field but I need > > the simulated value in a certain range. So I need some easy to use > > functions to generate a truncated Gaussian field to start with. To > > be specific, I need a function like GaussRF from the RandomFields > > package or grf from the geoR package to generate a random field, but > > I need the generated field to have a truncated marginal > > distributions and a correlation structure with a prescribed > > range. Is there an R package or functions which can do this? If > > there is no availabe read-to-use functions or packages,is it > > possible that I write my own very easily? > > As I suggested on Stack Overflow, I don't think this is a simple > question: you can pick values according to a normal distribution and > then squash them into a truncated normal distribution: something like > > olddata <- GaussRF(...) > library(truncnorm) > newdata <- qtruncnorm(pnorm(olddata)) > > However, this may very well modify the range; I don't know. > If I were you, I would try it and see if you can live with the > results. If not, ask on http://stats.stackexchange.com > > ______________________________________________ > R-help@r-project.org <mailto: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.
