Thanks Peter. I failed to realize earlier that one of the functions I used came from a package. The following solved the problem.
foreach(i = 1:length(splist)) %:% foreach(j = 1:length(covset), .packages = c("raster")) %dopar% { ....... On Thu, Dec 7, 2017 at 1:52 AM, Peter Langfelder <peter.langfel...@gmail.com > wrote: > Your code generates an error that has nothing to do with dopar. I have > no idea what your function stack is supposed to do; you may be > inadvertently calling utils::stack which would produce this kind of > error: > > > stack(1:25, RAT = FALSE) > Error in data.frame(values = unlist(unname(x)), ind, stringsAsFactors = > FALSE) : > arguments imply differing number of rows: 25, 0 > > HTH, > > Peter > > On Wed, Dec 6, 2017 at 10:03 PM, Kumar Mainali <kpmain...@gmail.com> > wrote: > > I have used foreach() for parallel computing but in the current problem, > it > > is not working. Given the volume and type of the data involved in the > > analysis, I will try to give below the complete code without reproducible > > example. > > > > In short, each R environment will draw a set of separate files, perform > the > > analysis and dump in separate folders. > > > > splist <- c("juoc", "juos", "jusc", "pico", "pifl", "pipo", "pire", > "psme") > > covset <- c("PEN", "Thorn") > > > > foreach(i = 1:length(splist)) %:% > > foreach(j = 1:length(covset)) %dopar% { > > > > spname <- splist[i]; spname > > myTorP <- covset[j]; myTorP > > > > DataSpecies = data.frame(prsabs = rep(1, 10), lon = rep(30, 10), lat = > > rep(80, 10)) > > myResp = as.numeric(DataSpecies[,1]) > > myRespXY = DataSpecies[, c("lon", "lat")] > > # directory of a bunch of raster files specific to each R environment > > rastdir <- paste0(rootdir, "Current/", myTorP); rastdir > > rasterc = list.files(rastdir, pattern="\\.tif$", full.names = T) > > print(rasterc) > > myExplc = stack(rasterc, RAT=FALSE) > > } > > > > I get the following error message that most likely generates while > stacking > > rasters because there are 25 rasters in the folder of each environment. > > Also, in the normal for loop, this reads all fine. > > Error in { : > > task 1 failed - "arguments imply differing number of rows: 25, 0" > > > > Thank you. > > ᐧ > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > > 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. > -- Postdoctoral Associate Department of Biology University of Maryland, College Park ᐧ [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.