Displaying 20 results from an estimated 1000 matches similar to: "reproducing Box-Muller numbers"
2002 Nov 26
5
unexpected behaviour of rnorm()
Hello everyone.
If I do
f <- function(n){max(rnorm(n))}
plot(sapply(rep(5000,4000),f)) #[this takes my PC about 30 seconds]
then I get something quite unexpected: gaps in the distribution. For
me, the most noticable one is at about 3.6.
Do others get this? Is it an optical illusion? It can't be right,
can it? Or maybe I just don't understand the good ol' Gaussian very
2008 Aug 17
1
Wichmann-Hill Random Number Generator and the Birthday Problem
Dear all,
Recently I am generating large random samples (10M) and any duplicated
numbers are not desired.
We tried several RNGs in R and found Wichmann-Hill did not produce
duplications.
The duplication problem is the interesting birthday problem. If there are
M possible numbers, randomly draw N numbers from them,
the average number of dupilcations D = N(N-1)/2/M.
For Knuth-TAOCP and
2008 Aug 14
2
[R] RNG Cycle and Duplication (PR#12540)
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I didn't describe the problem clearly. It's about the number of distinct=20
values. So just
1999 May 04
1
rnorm
Brian
I've been playing a bit with the Wichmann-Hill RNG. I would prefer to have
normally distributed random numbers and I think I have things generally worked
out to use Wichmann-Hill and then Box-Muller. In the process, I was looking at
R's rnorm.c, but could not figure out what transformation is used in R to
convert uniform rv's to normal rv's. Do you know? It looks like there
2019 Feb 26
2
bias issue in sample() (PR 17494)
Gabe
As mentioned on Twitter, I think the following behavior should be fixed
as part of the upcoming changes:
R.version.string
## [1] "R Under development (unstable) (2019-02-25 r76160)"
.Machine$double.digits
## [1] 53
set.seed(123)
RNGkind()
## [1] "Mersenne-Twister" "Inversion"??????? "Rejection"
length(table(runif(1e6)))
## [1] 999863
I don't
2019 Feb 19
2
bias issue in sample() (PR 17494)
Before the next release we really should to sort out the bias issue in
sample() reported by Ottoboni and Stark in
https://www.stat.berkeley.edu/~stark/Preprints/r-random-issues.pdf and
filed aa a bug report by Duncan Murdoch at
https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17494.
Here are two examples of bad behavior through current R-devel:
set.seed(123)
m <- (2/5) * 2^32
2019 Feb 26
1
bias issue in sample() (PR 17494)
Ralf
I don't doubt this is expected with the current implementation, I doubt
the implementation is desirable. Suggesting to turn this to
pbirthday(1e6, classes = 2^53)
## [1] 5.550956e-05
(which is still non-zero, but much less likely to cause confusion.)
Best regards
Kirill
On 26.02.19 10:18, Ralf Stubner wrote:
> Kirill,
>
> I think some level of collision is actually
1999 May 05
1
RNG R/Splus compatibility
Starting with example Wichmann-Hill code from Brian Ripley I have been playing
with a set of programs for getting the same random sequences from R and Splus. A
copy is included below along with a test (which works in Solaris with R and
Splus 3.3).
The approach is somewhat different from the usual problems on this list as I am
trying to get the same results from Splus as I get from R. However,
1999 Apr 28
1
R random number generator
R 0.64 on windows NT 4.0
Sometimes I got an error message by doing this
> .Random.seed <- c(1, 1:2)
> .Random.seed
[1] 1 1 2
> runif(5)
Warning: Wrong length .Random.seed; forgot initial RNGkind? set to Wichmann-Hill[1] 0.02253721 0.84832584 ........
Sometimes I do not get error message:
> .Random.seed <- c(1, 1:2)
> .Random.seed
[1] 1 1 2
> runif(1)
[1] 0.5641106
>
2003 Oct 20
1
Random Number Generator RNGkind() under "R CMD check" (PR#4691)
Full_Name: Wolfgang Huber
Version: 1.8.0
OS: Linux
Submission from: (NULL) (193.174.58.146)
The man page for RNGkind says that the default is Mersenne-Twister, and when I
start R interactively, I get in fact
> RNGkind()
[1] "Mersenne-Twister" "Inversion"
However, during the execution of "R CMD check" I get
> > ### ** Examples
> >
> > RNGkind()
2005 Nov 17
2
R questions
Dear Sir/Madam,
I am a beginner in R. Here is my questions.
1. Can you give me one test for randomness (a name and descriptive
paragraph is sufficient).
2. I have learned a uniform random number generator [e.g. not the
algorithms: i)Wichmann-Hill, ii) Marsaglia-Multicarry, iii) Super-Duper
(Marsaglia), iv) Mersenne-Twister, v) TAOCP-1997 (Knuth), or vi) TAOCP-2002
(Knuth)] . Is there any other
2003 Jan 28
5
random number generator?
Dear R-Aficionados:
I realize that no random number generator is perfect, so what I report
below may be a result of that simple fact. However, if I have made an
error in my thinking I would greatly appreciate being corrected.
I wish to illustrate the behavior of small samples (n=10) and so
generate 100,000 of them.
n.samples <- 1000000
sample.size = 10
p <- 0.0001
z.normal <- qnorm(p)
2003 Apr 25
4
Kinderman-Ramage (PR#2846)
Hi,
Our department has detected a bug in the implementation of the
Kinderman-Ramage generator for normal random variates in version
1.7.0, which can be seen from the below R session.
(Consecutive calls for chisq.test(...) always gives p-values very
close to 0.)
We have already encountered this bug in version 1.6.2
The error is in file
R-1.7.0/src/nmath/snorm.c
Here is a patch for this file to
2018 Mar 04
2
Random Seed Location
The following helps identify when .GlobalEnv$.Random.seed has changed:
rng_tracker <- local({
last <- .GlobalEnv$.Random.seed
function(...) {
curr <- .GlobalEnv$.Random.seed
if (!identical(curr, last)) {
warning(".Random.seed changed")
last <<- curr
}
TRUE
}
})
addTaskCallback(rng_tracker, name = "RNG tracker")
EXAMPLE:
>
2018 Mar 04
0
Random Seed Location
On 04/03/2018 5:54 PM, Henrik Bengtsson wrote:
> The following helps identify when .GlobalEnv$.Random.seed has changed:
>
> rng_tracker <- local({
> last <- .GlobalEnv$.Random.seed
> function(...) {
> curr <- .GlobalEnv$.Random.seed
> if (!identical(curr, last)) {
> warning(".Random.seed changed")
> last <<- curr
2002 Aug 12
1
set.seed
I'm running into problems with set.seed--maybe I'm misunderstanding
something.
I'm running R 1.5.1 on Windows 2000.
I'm basically trying to capture the random seed so that I can reproduce a
simulation if it's necessary later. Using set.seed, I can certainly get
reproducible results, but not the results I get on the first pass. Here's
an example:
# Generate a random
2008 Aug 14
2
RNG Cycle and Duplication
Hello all,
I am generating large samples of random numbers. The RNG help page says:
"All the supplied uniform generators return 32-bit integer values that are
converted to doubles, so they take at most 2^32 distinct values and long
runs will return duplicated values." But I find that the cycles are not
the same as the 32-bit integer.
My test indicated that the cycles for
2008 Aug 19
1
RNGkind() state (PR#12567)
I sent this to R-devel early last month, but have received no response, so I guess it
really is a bug.
This looks like a bug to me, and is a bit hard to describe, but easy to reproduce. ?
Basically, if RNGkind is saved as something other than the default, and if the first
operation in a session is a set.seed(), the default is reverted to. ?Reproduce by:
cafe-rozo> ?R --vanilla
R version
2017 Apr 02
3
samba Digest, Vol 172, Issue 2
On Sun, 2 Apr 2017 19:02:35 +0200
Karl Heinz Wichmann via samba <samba at lists.samba.org> wrote:
> Hallo Marc
>
> I change the loglevel to 10
>
>
> database
> "dlopen /usr/lib/x86_64-linux-gnu/samba/bind9/dlz_bind9_9.so -d 10";
>
> and i get following errors:
>
> 02-Apr-2017 18:47:44.389 samba_dlz: ldb: ldb_asprintf/set_errstring:
> No
2015 Jul 06
1
Rejoin dc to domain
Dear Davor
We receive an error message at the command "list domains"
ntdsutil
metadata cleanup
connections
connect to server <DC with fsmo roles>
quit
select operation target
error: error at handling the input
invalid syntax
-> list domains
But the command is correct!
Am 02.07.2015 um 21:11 schrieb Davor Vusir:
> You might need to do a meta data cleanup before