similar to: Error of 'memory not mapped' in ff Package with VirtualBox

I've spent some time trying to wrap my head around reading in large csv files with the ff-package. I think I know how to do it, but am bumping into some problems. I've tried to recreate the issues as best as I can with a smaller example and maybe someone can help explain the problems. The following code just creates a csv file with an integer column, character column and logical column.

Dear list, I am trying to understand and use the ff package. As I had some problems saving some ff objects, and as I did not fully manage to understand the whole concept of *.ff, *.ffData and *.RData with the help of the documentation, I tried to reproduce the examples from the help of ffsave. When I ran, however : (copied from the help) message("let's create some ff objects")

Hi, The read.csv.ffdf function in package ff will create the ff object physical file in the default directories, I am trying to let the files created in the paths users specify, I think the point is to make use of the asffdf_args parameter, I have a test CSV file named D:\rtemp\fftest.csv, the content of the file is as following: col1,col2,col3 1,"amber",2.4 2,"linda",4.5

Dear Fellows, I would like to know how to uncompress a gz file at the R console. I could not find out any help from the R-help archive. Thanks for your great help. Best Regards, Wonsang You ----- -- Wonsang You Special Lab Non-Invasive Brain Imaging Leibniz Institute for Neurobiology http://www.ifn-magdeburg.de -- View this message in context:

Hi, I have two questions on using the ff package and wonder if anyone who used ff can share some thoughts. I need to save a matrix as a memory-mapped file and load it back later. To save the matrix, I use mat = matrix(1:20, 4, 5) matFF = ff(mat, dim=dim(mat), filename="~/a.mat", overwrite=TRUE, dimnames = dimnames(mat)) To load it back, I use matFF2 = ff(vmode = "double",

Really old subject?, so, all my apologizes for digging up but, since I also ran into this? maybe this hack can be useful to someone I propose monkey patching here: library(ff) my.as.ffdf.data.frame <- function (x, vmode = NULL, col_args = list(), ...) { rnam <- attr(x, "row.names") if (is.integer(rnam)) { if (all(rnam == seq_along(rnam))) rnam <- NULL else

Dear fellows, I am a novice in R. I would like to combine a matrix and a vector. Assume that we have the matrix a and the vector b with same length of column. a<-matrix(seq(1:10),nrow=2,ncol=5,byrow=TRUE) a= 1 2 3 4 5 6 7 8 9 10 b<-t(c(11,12,13,14,15)) b= 11 12 13 14 15 Then, I want to combine a and b as follows. c= 1 2 3 4 5 6 7 8 9

Hi, I am using version 2.1-1 of the ff package. I have a data set with 80 million rows and I need to create a new ffdf object, subseting by values in one of the original ffdf's columns. Here is my code: bigData <- read.table.ffdf(file="/data/demodata/data/smallData.txt", next.rows=1e5, head=TRUE, sep="|") dim(bigData) N <- nrow(bigData);N select <- ff(

I'm having trouble getting ffdfindexget to work right in Windows. Even the most trivial of examples gives me problems. > myVec = ff(1:5) > another = ff(10:14) > littleFrame = ffdf(myVec, another) > posVec = ff(c(2, 4), vmode = 'integer') > ffdfindexget(littleFrame, posVec) Error in if (any(B < 1)) stop("B too small") : missing value where TRUE/FALSE

Dear R Helpers, I have attempted "optim" function to solve a two-dimensional optimization problem. It took around 25 second to complete the procedure. However, I want to reduce the computation time: less than 7 second. Is there any optimization function in R which is very rapid? Best Regards, Wonsang ----- Wonsang You Leibniz Institute for Neurobiology -- View this message in

Hi Does anybody know how to create ff objects with data reading from stream objects, such as data reading from PostgreSQL database through RPostgreSQL. For this purpose although we can save the data to a csv file through external tools and then read it through csv readers, but it requires one more data read and write operation, which is of high I/O cost for large datasets. Xiaobo.Gu

I've noticed that ff uses the unzip utility available on it's host OS to load datasets via ffload. It seems to work fine in linux, but when I try to use the package in Windows (hence dling Windows unzip utils) I get 2 errors, one telling me that the options aren't being passed to unzip correctly and another indicating that my filename is incorrect. First, does anyone know of an unzip

Hi, R-Helpers, I would like to ask about multiple graphs in one figure. I tried to execute the following codes. xlim <- c(1,100) ylim <- c(1,4) plot(NA, xlim=xlim, ylim=ylim) > x <- c(1:100) for(j in seq(1,10,by=1)) { y <- j*x^2+log(j) lines(x, y) } In the above codes, I had to arbitrarily set up the coordinate range of the figure in advance before

Greetings useRs, Can anyone provide an example how to use ff to feed a very large data frame to glm? The data.frame cannot be loaded in R using conventional read.csv as it is too big. glm(...,data=ff.file) ?? Thank you Stephen B

Dear R user fellows, I would like to ask you about the package 'rgenoud' which is a genetic optimization tool. I ran the function 'genoud' with two variables to be minimized by the following command. result<-genoud(fn,nvars=2,starting.values=c(0.5,0), pop.size=1000, max.generations=10, wait.generations=3) Then, I had the following error message. Error in

Dear R friends. After having some troubles learning how to create a ffdf object, now I find myself having problems saving it. this is the data i´d like to save: str(DATA) List of 3 $ virtual: 'data.frame': 6 obs. of 7 variables: .. $ VirtualVmode : chr "double" "short" "integer" "integer" ... .. $ AsIs : logi FALSE FALSE FALSE

Hi, I am running the examples in page 70 of the ff package document, but it failed with the following error > cat("let's create some ff objects\n") let's create some ff objects > n <- 8e3 > a <- ff(sample(n, n, TRUE), vmode="integer", length=n, filename="d:/tmp/a.ff") > b <- ff(sample(255, n, TRUE), vmode="ubyte", length=n,

Dear R-Helpers, I want to try the 2D (two-dimensional) convolution in R. For example, let us we have the following kernel and data. kernel <- (1,2,3,2,1) data <- array(1:100, dim=c(10,10)) I know the function 'convolve' only for one-dimensional convolution, but it is just for a 1D sequence. Is there any function for 2D convolution? For theory, please refer to the following link:

Dear R Helpers, I have searched for any R package or code for simulating multivariate fractional Brownian motion (mFBM) or multivariate fractional Gaussian noise (mFGN) when a covariance matrix are given. Unfortunately, I could not find such a package or code. Can you suggest any solution for multivariate FBM and FGN simulation? Thank you for your help. Best Regards, Ryan ----- Wonsang You

Dear R community, The next release of package ff is available on CRAN. With kind help of Brian Ripley it now supports the Win64 and Sun versions of R. It has three major functional enhancements: a) new fast in-memory sorting and ordering functions (single-threaded) b) ff now supports on-disk sorting and ordering of ff vectors and ffdf dataframes c) ff integer vectors now can be used as