similar to: computational capacity of Linux network

Dear R-Users, I have a data file with timestamps and I wanted to use POSIXct time data type to represent the respective column. I played around with the type and found a couple of issues: * there seems to be no direct way of reading datetimes into a variable. Let's say this is my file "1992-02-27 23:03:20 PST" "1992-02-27 22:29:56 PST" "1992-01-14 01:03:30 PST"

Dear R-Users, I have the following problem to solve and I wonder if there are means in R that can help me. At irregular time intervals I observe a random walk process, Y, with time-varying drift. I assume that the drift, D, is a (linear) function of some parameter X. The goal is to estimate D(X). I could regress Y_{t+dt} - Y_{t} ~ X, but it's probably not appropriate since Var(Y_{t+dt} -

Dear R-Users, I am reading the "An Introduction to R" manual and have come across data() function for loading data. I assume that R requires explicit loading of data objects to save memory. Then I'd expect there should be a function that can unload the objects once they are not needed anymore, what is this function? It would be helpful if ?data contained a reference to that

Dear R-Users, I need to find a smooth function f() and coefficients a_i that give the best fit to y ~ a_0 + a_1*f(x_1) + a_2*f(x_2) Note that it is the same non-linear transformation f() that is applied to both x_1 and x_2. So my first question is how can I do it in R? A more general question is this: suppose I have a utility function U(a_i, f()), where f() is say a spline. Is there a general

Hi, I need "mutable" objects that I can safely modify in my C code. All call interfaces, e.g. .C, .Call, etc., require you to not modify the "in" args. The description of the OOP package in R-news from Sep 2001 alludes to a possiblity of such objects, but the package itself is no longer on Omegahat and I am not sure I need the full machinery. Thanks, Vadim P.S. I wonder

Hi, Does anyone have an example of calling optim() from a standalone C/C++ program? If possible please include the linker options (I am using gcc version 2.96 20000731 (Red Hat Linux 7.1 2.96-98)) Thanks, Vadim -------------------------------------------------- DISCLAIMER This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain

An embedded message was scrubbed... From: Douglas Bates <bates at stat.wisc.edu> Subject: Re: [R] Are you experienced in SAS and R as well? Which of these would you recommend me? Date: 23 Nov 2001 15:16:59 -0600 Size: 4446 Url: https://stat.ethz.ch/pipermail/r-help/attachments/20011123/8d0399f0/attachment.mht

Hi, Is there a direct way of listing objects loaded by load() command? I worked around by loading into a new environment and then ls() of that environment, but I wonder if there is a simpler way. Thanks, Vadim -------------------------------------------------- DISCLAIMER This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally

Dear R-Users, I have a csv file that has NA tokens and these tokens are perfectly good values that need not to be converted to NA by read.table(). I tried to prevent the conversion by specifying the na.strings arg., but this seems to only add to the list of NA strings, not substitute. > system("cat foo") system("cat foo") 1 foo 2 NA > read.table("foo",

Dear R-Users, It seems like once one invokes browser() inside a loop and steps through the body using 'n' any subsequent loop will be "intercepted" by debug() function. Here is exactly what I mean # fresh R session # run a loop that has browser() inside the body > for (i in seq(5)) { browser(); print(i) } for (i in seq(5)) { browser(); print(i) } Called from: NULL

Hi, I thought it would be convenient if the check.names argument to read.table, which currently can only be TRUE/FALSE, could take a function value as well. If the function is supplied it should be used instead of the default make.names. Here is an example where it can come in handy. I tend to keep my data in coma-separated files with a header line. The header line is prefixed with a comment

Dear R users, I am looking for a reference to an algorithm for estimation of sample quantiles which does not require bringing the whole data into memory (more precisely its memory complexity should be much less than linear, ideally constant). I realize that such an algorithm can only be approximate and actually quite wrong for some samples, but that's fine with me. Thank you, Vadim

Hi, Is it possible to modify an object in the parent.env (as opposed to re-bind)? Here is what I tried: > x = 1:3 # try to modify the first element of x from within a new environment > local(get("x", parent.env(environment()))[1] <- NA) Error in eval(expr, envir, enclos) : Target of assignment expands to non-language object # On the other hand retrieval works just fine >

Hi, As was discussed earlier in another thread and as documented in R-exts .Call() should not be interruptible by Ctrl-C. However the following code, which spends most of its time inside mkChar, turned out to be interruptible on RH-7.3 R-1.8.1 gcc-2.96: #include <Rinternals.h> #include <R.h> SEXP foo0(const SEXP nSexp) { int i, n; SEXP resSexp; if (!isInteger(nSexp))

Hi, I tried to write the dim method for the list class, but R doesn't seem to dispatch to it: > dim.list = function(x) c(length(x[[1]]), length(x)) > dim(list(1)) NULL > dim.list(list(1)) [1] 1 1 What is the correct way of registering dim.list with .Primitive("dim")? Thanks, Vadim [[alternative HTML version deleted]]

Hi, I am looking for an efficient way of skipping big chunks of lines on a connection (not necessarily at the beginning of the file). One way is to use read lines, e.g. readLines(1e6), but a) this incurs the overhead of construction of the return char vector and b) has a (fairly remote) potential to blow up the memory. Another way would be to use scan(), e.g. scan(con, skip=1e6, nmax=0)

Hi, I am trying to figure a way to allocate a string SEXP so that gc() won't ever collect it. Here is a little bit of a background. Suppose I want to write a .Call-callable function that upon each call returns the same value, say mkChar("foo"): SEXP getFoo() { return mkChar("foo"); } The above implementation doesn't take advantage of the fact that

Hi, I am having a problem to understand why as.data.frame method doesn't dispatch properly on my class: > setClass("Foo", "character") [1] "Foo" > as.data.frame(list(foo=new("Foo", .Data="a"))) Error in as.data.frame.default(x[[i]], optional = TRUE) : can't coerce Foo into a data.frame I was expecting that this would call

Hi, What is the reason for seq.Date to require the 'by' argument and not to default it to 1 in the example below? > seq(from=as.Date("1996-01-01"), to=as.Date("1996-12-01")) Error in seq.Date(from = as.Date("1996-01-01"), to = as.Date("1996-12-01")) : exactly two of `to', `by' and `length.out' / `along.with' must be specified

Well, "integer" is also a storage.mode in R. It is not immediately clear which meaning the help page uses. I guess some extra elaboration would be helpful. Anyway, thank you for the clarification, Vadim > -----Original Message----- > From: Prof Brian Ripley [mailto:ripley@stats.ox.ac.uk] > Sent: Tuesday, March 22, 2005 9:54 AM > To: Vadim Ogranovich > Cc: