Michael Kubovy wrote: > Dear r-helpers, > > In my previous message there were comments in the code that may have > made cutting and pasting awkward. Here it is w/o them. > > I have two questions: > > (1) The following produces a pdf with artifacts. How do I prevent them? >
What artifacts do you see? It looks like a smoothly varying field when produced by R 2.5.1 and viewed in Acrobat Reader 6.0 on Windows. Duncan Murdoch > require(grDevices) > imSize <- 200 > lambda <- 10 > theta <- 15 > sigma <- 40 > x <- 1:imSize > x0 <- x / imSize -.5 > freq = imSize/lambda > xf = x0 * freq * 2 * pi > f <- function(x, y){r <- -((x^2 + y^2)/(sigma ^2)); exp(r)} > z <- outer(xf, xf, f) > f1 <- function(x, y){cos(.1 * x)} > z1 <- outer(xf, xf, f1) > pdf('gabor.pdf') > image(xf, xf, z * z1, col = gray(250:1000/1000), > xlab = '', ylab = '', bty = 'n', axes = FALSE, asp = 1) > dev.off() > > (2) I would like the output to be clipped to a circle, i.e., anything > outside the circle tangent to the sides of the square should be > transparent. How can I do that? Set the values there to NA? I'm not sure how ragged that will make the edge... ______________________________________________ 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.