Displaying 20 results from an estimated 9000 matches similar to: "random number generator?"
2008 Aug 14
5
help with my sloppy syntax
R-ians:
After some effort I coerced my code to do what I want but my syntax is a
kludge. Suggestions on more elegant syntax?
par <- NIM.results$par
do.call("Draw.NIM.POD.curve", list(par[1], par[2], par[3], par[4],
par[5], a.hat.decision, .... et cetera ...
It seems that I should be able to avoid defining the variable "par" and then
specifying each of its elements,
2019 Feb 26
2
bias issue in sample() (PR 17494)
Gabe
As mentioned on Twitter, I think the following behavior should be fixed
as part of the upcoming changes:
R.version.string
## [1] "R Under development (unstable) (2019-02-25 r76160)"
.Machine$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
2009 Nov 16
2
(Parallel) Random number seed question...
Hi All,
I have k identical parallel pieces of code running, each using n.rand
random numbers.? I would like to use the same RNG (for now), and set
the seeds so that I can guarantee that there are no overlaps in the
random numbers sampled by the k pieces of code.? Another side goal is
to have reproducibility of my results.? In?the past I have used C with
SPRNG for this task, but I'm hoping
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
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()
2018 Mar 04
3
Random Seed Location
On Mon, Feb 26, 2018 at 3:25 PM, Gary Black <gwblack001 at sbcglobal.net>
wrote:
(Sorry to be a bit slow responding.)
You have not supplied a complete example, which would be good in this
case because what you are suggesting could be a serious bug in R or a
package. Serious journals require reproducibility these days. For
example, JSS is very clear on this point.
To your question
>
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
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$.Random.seed
if (!identical(curr, last)) {
warning(".Random.seed changed")
last <<- curr
}
TRUE
}
})
addTaskCallback(rng_tracker, name = "RNG tracker")
EXAMPLE:
>
2006 Aug 28
1
Speed of runif() on different Operating Systems
Dear list,
I have noticed surprisingly big performance differences of runif()
between Windows XP and (Debian) linux on similar CPUs (Pentium D 3.0GHz
(WinXP)/3.2GHz (Linux)) and I wonder if there is a simple explanation
for the difference.
On a linux system (with a slightly better CPU and 1GB more RAM),
execution of runif() seems to consume about 80% more CPU time than on a
Windows XP
2016 Aug 31
1
A bug in the R Mersenne Twister (RNG) code?
On 30 August 2016 at 18:29, Duncan Murdoch wrote:
| I don't see evidence of a bug. There have been several versions of the
| MT; we may be using a different version than you are. Ours is the
| 1999/10/28 version; the web page you cite uses one from 2002.
|
| Perhaps the newer version fixes some problems, and then it would be
| worth considering a change. But changing the default RNG
2018 Mar 04
0
Random Seed Location
On 04/03/2018 5:54 PM, Henrik Bengtsson wrote:
> The following helps identify when .GlobalEnv$.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
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
2005 Feb 21
4
rnorm??
I am wondering whether there is a bug in rnorm.
When generating rnorm(1000000) and counting
the cases > 4 and the cases < (-4) I get rather
unexpectedly low counts for the latter. The problem goes away
when using qnorm(runif(1000000)).
Fritz Scholz, PhD
Applied Statistics Group
Boeing Phantom Works
fritz.scholz at pss.boeing.com
425-865-3623
Tu/We 206-542-6545 (most likely)
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
2015 Feb 08
3
Which function can change RNG state?
Today I struggled for hours to understand some unexpected package test
results. It turned out that this is because package "parallel", buried deep
in my dependencies, calls runif() during it's initialization and in this way
changes the random number sequence. This seems to be a part of a more
general question--which kind of functions can we trust if we want to
preserve random
2013 Feb 18
2
Random number generator used in 'runif'
Dear list,
For the implementation of a particular optimization algorithm it is
very important the random number generator.
I would like to know if somebody could tell me what is the random
number generator used by default in the 'runif' function.
>From the help page of 'runif' and '.Random.seed' I guess that the
default algorithm is 'Mersenne-Twister', but I
2018 Mar 04
0
Random Seed Location
Thank you, everybody, who replied! I appreciate your valuable advise! I will move the location of the set.seed() command to after all packages have been installed and loaded.
Best regards,
Gary
Sent from my iPad
> On Mar 4, 2018, at 12:18 PM, Paul Gilbert <pgilbert902 at gmail.com> wrote:
>
> On Mon, Feb 26, 2018 at 3:25 PM, Gary Black <gwblack001 at sbcglobal.net>
>
2006 Sep 29
3
control L to clear the Rgui screen in Windows
Greetings R-ians:
Searching the Searchable Mail Archives I discovered that ctrl L will clear
the Rgui screen, which is what I'd like to do from a print (or some similar)
statement.
Is there a mechanism to use the ctrl L clear-screen sequence in a script, or
print statement?
Thanks for your counsel.
Charles Annis, P.E.
Charles.Annis at StatisticalEngineering.com
phone: 561-352-9699
eFax:?