Hi All,
I am new in R and trying to simulate random normal 2D field with mean trend
say north-south. My domain is 10x10 grid and I am trying to use mvnorm but do
not know how to specify the domain and the mean field.
I would appreciate any help.
Cheers, SK
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Hi SK, If I understand you correctly you are trying to assign to each point of a 10x10 2D grid a normal variable with a certain dependency between the values at each grid point. Is this correct? If so, please explain the dependence structure. Do you need something like X(i,j) = f(i,j) + Z(i,j) for 1<=i,j<=10 where f is a deterministic function and Z(i,j) are independent normal variables? Or do you want to assume that Z(i,j) have a multivariate normal distribution (and can specify the covariance matrix)? Regards, Moshe. --- sk <sdk0084 at yahoo.com> wrote:> Hi All, > I am new in R and trying to simulate random normal > 2D field with mean trend say north-south. My domain > is 10x10 grid and I am trying to use mvnorm but do > not know how to specify the domain and the mean > field. > I would appreciate any help. > Cheers, SK > > > --------------------------------- > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at stat.math.ethz.ch 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. >
Hello SK, I suggest you try the RandomFields package. It has specific functions for simulating random fields with an array of different algorithms and distributions. The GaussRF function in particular normal generates random fields. Julian Julian M. Burgos Fisheries Acoustics Research Lab School of Aquatic and Fishery Science University of Washington 1122 NE Boat Street Seattle, WA 98105 Phone: 206-221-6864 sk wrote:> Hi All, > I am new in R and trying to simulate random normal 2D field with mean trend say north-south. My domain is 10x10 grid and I am trying to use mvnorm but do not know how to specify the domain and the mean field. > I would appreciate any help. > Cheers, SK > > > --------------------------------- > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at stat.math.ethz.ch 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. > >