similar to: Re: [R] Strange means of numbers drawn from rpois (PR#729)

On 8 Nov 2000, Peter Dalgaard BSA wrote: >Done... Great! >(This kind of behaviour has been observed on various platforms and >various compilers, sometimes getting stuck around 15.15 and sometimes >around 14.5. Others report no problems. Very strange. I've seen one >case where it apparently shifted from one regime to the other.) Yes, it does that here too.... The following is

Dear all, I think I must be going crazy.... If I do > mean(rpois(1000000, 14)) I get: [1] 13.50420 and again: > mean(rpois(1000000, 14)) [1] 13.49896 > mean(rpois(1000000, 14)) [1] 13.50161 > mean(rpois(1000000, 15)) [1] 14.49250 > mean(rpois(1000000, 15)) [1] 14.49897 > mean(rpois(1000000, 14.5)) [1] 13.99689 > mean(rpois(1000000, 14.5)) [1] 13.9963 This was on a platform

Kjetil Kjernsmo <kjetil.kjernsmo@astro.uio.no> writes: > On 8 Nov 2000, Peter Dalgaard BSA wrote: > > >> > range(sapply(1:2000, function(n) mean(rpois(10000, c(15,15+1e-8))))) > >> [1] 14.8692 15.1200 > > > >AHA! Spotted, I think. > > Wow! Great, that was fast! > > >It is possible to return from rpois in step N, > >in which case

Full_Name: Kjetil Kjernsmo Version: 0.65.1 OS: Digital UNIX 4.0 Submission from: (NULL) (129.240.28.172) I'm experiencing problems with rpois. Occasionally, it draws a very high number. Yeah, I know, this is statistics, things like that does happen, but this really strange because a poisson distribution with a parameter of 3 shouldn't see the number 1932 very often, but the same,

Dear all, I'm a bit confused about the output from functions that generates random values, e.g. rpois. I'm using 0.65.1 on Digital UNIX alphaev6. If I say > rpois(10,5) output is not unexpectedly: [1] 4 6 5 7 6 5 2 2 5 3 but I figured that if I go: > rpois(10,1:10) I would get a 10x10 matrix as output, with random values for each of the vector elements in the row vectors, but

Full_Name: Kjetil Kjernsmo Version: Version 1.0.0 OS: osf1 Submission from: (NULL) (129.240.28.227) Dear all, I have come across another really strange bug in rpois. If I do > rpois(1, 1000000 * rpois(1, 10000)) sometimes it hangs, and hangs... On my XP1000 alphaev6 workstation, it seems to happen more frequently than on other machines. I started a session on an older computer, and from

Dear all, I have some difficulty getting R-1.3.0 to run on the alpha, with osf4.0e (Tru64, or whatever they call it... :-) ). configure reports the following configuration: R is now configured for alphaev6-dec-osf4.0e Source directory: . Installation directory: /astro/local C compiler: gcc -mieee -g -O2 C++ compiler: c++ -g -O2 FORTRAN

Dear all, I have some difficulty getting R-1.3.0 to run on the alpha, with osf4.0e (Tru64, or whatever they call it... :-) ). configure reports the following configuration: R is now configured for alphaev6-dec-osf4.0e Source directory: . Installation directory: /astro/local C compiler: gcc -mieee -g -O2 C++ compiler: c++ -g -O2 FORTRAN

Dear all, Either I'm being totally blind now (as you know, the eyes are the first thing that is blinded :-)), or something is missing in "An Introduction to R". The section heading of section 5.7.1 is "Multiplication, inversion and solving linear equations", and since I was looking for the canonical way of inverting a matrix, this was the place to look. However, I found

Dear all, I have been away for a month, but some time ago, I noted something that was very surprising to me. I think this example illustrates it well: > test <- data.frame(col1 = c(1,2), col2=c(3, 4)) > test col1 col2 1 1 3 2 2 4 > apply(test, 1, function(x) browser()) Called from: FUN(newX[, i], ...) Browse[1]> x$col1 NULL Browse[1]> x[["col1"]] [1] 1

Dear all, I have a few files with binary data written by a C program a friend wrote. I allready have program to read these files, Thomas Lumley and Prof Brian D Ripley was kind enough to respond to a question to this list earlier with some code that works perfectly, so this is really no problem, it is more out curiousity. Most of my files consists of 40000 single precision floats, and I figured

Full_Name: Kjetil Kjernsmo Version: 1.0.1 OS: osf1 Submission from: (NULL) (129.240.28.227) Hello! I'm getting strange numbers from a random number generation function again. I was wondering if it could be the same problem as I reported in (PR#439). I'm using the functions (some comments deleted for brevity): qamp <- function(p, type=c("point", "nolens")) {

Dear all, There has been some time since I asked about interpolation in higher (>2) dimensions, and I must admit I failed to write a function to do this myself the last time, but eventually ended up doing it in MATLAB. I tried to translate the MATLAB code, but MATLAB code is so much more opaque than R (S) code, so I failed that too, mainly because I could only get one MATLAB session, I would

Dear all, I'm generally not a big fan of GUIs, but I have just discovered one thing where a GUI would be a nice thing: creating color palettes. I'm creating an "image", for transparencies for a lecture I'm giving, so this is going to look great... :-) What I'm out for, is to make green tones and red tones, and a relatively sharp break between them. This break will

Full_Name: Kjetil Kjernsmo Version: 1.1.1.1 (patched the rpois :-)) OS: osf4.0e Submission from: (NULL) (129.240.28.227) Dear all, I have just gotten through a debugging session of my code, being confused for a few days. I sent what I thought was a straightforward matrix to chisq.test() and once in a while got the error message: > chisq.test(t2) Error in chisq.test(t2) : missing value where

Dear all, Me and the Garbage Collector doesn't understand each other... I'm on R-1.0.1 (I have requested an upgrade to the right local people), an osf1 system with an alphaev6 CPU. I have fair amounts of memory to use, but it seems to be used up pretty fast nevertheless. I'm now trying to see what the garbage collector does, I have inserted a gc(v=T) call at a spot in my code. I

Full_Name: Kjetil Kjernsmo Version: Version 1.0.0 OS: osf1 Submission from: (NULL) (129.240.28.227) Hello again! This is a follow-up to my message on R-help about a problem with match.arg() I have a little more on the topic, but not much really. First, it was not entirely true what I wrote in r-help that I call match.arg() in my ramp(), because ramp() just calls qamp() with runif() as

Dear all, I have an image that I need to filter, and so I'm looking for a method to convolve it with a matrix. If I understood the docs for convolve correctly, it only works in 1D (and I have tried to convolve, it didn't look good). So, I wondered if anybody have implemented 2D convolution in R, or have any good advices to share (beyond having a look at mvfft), before I go hacking?

Dear all, I'm a bit concerned about underflow problems. Such problems typically occur when two almost equal numbers are subtracted. I was wondering if R has any mechanisms for warning users about potential problems, or if any policy has been developed? To check, I just did: > 1.0000000000000001 - 1 [1] 0 > 1.000000000000001 - 1 [1] 1.110223e-15 > 1.00000000000001 - 1 [1]

Dear all, A looong time ago, Witold Eryk Wolski asked here why there wasn't a log="xy" parameter to the hist() function <URL:http://www.R-project.org/nocvs/mail/r-help/2001/0267.html>, and Prof. Ripley responded that a loglog histogram does not make much sense, and that one should use a better density estimate if one seeks to plot log density. I understand the point and I