Someone inquired on StackOverflow about apparently non-deterministic graphics behaviour in R. I noticed that they were using cex="*" and discovered some potentially weird behavior.
On repeated runs of the same code I can get different PNGs. If I set the number of runs high enough, I seem to be able to get R to hang. If I do a single version plotting to an interactive graphics window I can get the point sizes to jump around as I resize the window (someone reported being able to reproduce that behaviour in the Windows GUI as well). This is clearly a user error, but non-deterministic behaviour (and hanging) are a little disturbing. I haven't had a chance yet to try to dig in and see what's happening but thought I would report to see if anyone else could reproduce/figure it out. Ben Bolker ######################## ## n <- 100 ## hangs R n <- 33 fn <- paste("tmp",seq(n),"png",sep=".") for (i in seq(n)) { png(fn[i]) plot(1:10,1:10,cex="*"); dev.off() } ff <- subset(file.info(fn),select=size) ff <- ff[!duplicated(ff$size),,drop=FALSE] table(ff$size) require(png) pngs <- lapply(rownames(ff),readPNG) png.to.img <- function(x) matrix(rgb(x[,,1],x[,,2],x[,,3]), nrow=dim(x)[1],ncol=dim(x)[2]) imgs <- lapply(pngs,png.to.img) par(mfrow=c(2,2)) lapply(imgs,function(x) { plot(0:1,0:1,type="n",ann=FALSE,axes=FALSE) rasterImage(x,0,0,1,1) }) ######################### > sessionInfo() R Under development (unstable) (2011-10-06 r57181) Platform: i686-pc-linux-gnu (32-bit) attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] glmmADMB_0.6.5 MASS_7.3-14 png_0.1-3 loaded via a namespace (and not attached): [1] grid_2.15.0 lattice_0.19-33 nlme_3.1-102 tools_2.15.0 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel