Hi Ryan, I think that the only function you need is the one which generates random variable. The simplest one is to generate a uniform (0,1) variable U and then do not move if U < 0.25, move to the first nearest point if 0.25 <= U < 0.5, move to the second nearest point if ).5 <= U < 0.75 and move to the third nearest point if U >= 0.75. To make things work faster you may wish to prepare for which of your points the indexes of the 3 nearest points (i.e. if you have N points you prepare an Nx3 matrix of indexes).
Regards, Moshe. --- Ryan Briscoe Runquist <[EMAIL PROTECTED]> wrote: > > Hello, > > I am trying to write a simulation to generate a null > hypothesis so that I > can test my data. Essentially we started out with a > grid of points and I > have a symmetrical matrix of the distance between > all of these points. I > then want to simulate random movement. So I want to > be able to start at a > point, search through the matrix for the three > closest points and with > equal probability move to one of them or stay at the > same place and then > record the distance moved as well as the relative > elevation (a vector of > data that I also have) and then starting at that > grid-point repeat the > process a number of times. Does anyone know of a > function that could help > me with this? > > Thanks, > Ryan > > > ~~~~~~~~~~~~~~~~~~ > Ryan D. Briscoe Runquist > Population Biology Graduate Group > University of California, Davis > [EMAIL PROTECTED] > > ______________________________________________ > R-help@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. > ______________________________________________ R-help@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.
