Dear Jeff, This is not exactly what you are asking, but what I do is close the object, save it as RData, and then when I need to load the RData. The RData objects themselves are very small.
Best, R. On Wed, Nov 25, 2009 at 2:28 AM, Hao Cen <h...@andrew.cmu.edu> wrote: > 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", dim= ???, filename="~/a.mat", overwrite=F) > > However, I don't always know the dimension when loading the matrix back. > If I miss the dim attributes, ff will return it as vector. Is there a way > to load the matrix without specifying the dimension? > > The second question is that the matrix may grow in terms of the number of > rows. I would like to synchronize the change to the memory-mapped file. Is > there an efficient way to do this? > > Thanks > > Jeff > > ______________________________________________ > R-help@r-project.org 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. > -- Ramon Diaz-Uriarte Structural Biology and Biocomputing Programme Spanish National Cancer Centre (CNIO) http://ligarto.org/rdiaz Phone: +34-91-732-8000 ext. 3019 ______________________________________________ R-help@r-project.org 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.