Displaying 20 results from an estimated 100 matches similar to: "set.seed"
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
2008 Jul 07
0
RNGkind() state
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 2.7.1 (2008-06-23)
Copyright (C) 2008 The R Foundation for Statistical Computing
ISBN 3-900051-07-0
R is
2001 Oct 18
0
uniform generator (default)
Recieving digests.
> RNGkind(NULL)
[1] "Marsaglia-Multicarry" "Kinderman-Ramage"
I would appreciate it if anybody has any comments on the following.
Please do not comment on the R functions themselves, since they merely
mimic a (bivariate simplification of a) C routine called from S.
In particular, I would like to know if anything is available with regard
to the
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
2011 Mar 04
2
apply.rolling() to a multi column timeSeries
Hello there,
I am trying to compute the 3 months return momentum with the timeSeries x.ts,
which is just a subset of simple returns from a much bigger series,
> class(x.ts)
[1] "timeSeries"
attr(,"package")
[1] "timeSeries"
> dim(x.ts)
[1] 20 3
> x.ts[1:8,]
GMT
MS.US AAPL.US CA.FP
1996-01-31 0.15159065 -0.133391894
2008 Mar 14
1
Buggy Kinderman-Ramage (PR#2846)
Unfortunately, RNGkind is buggy. It will not generate warnings
except the full name "Buggy Kinderman-Ramage" is supplied for normal.kind.
match.arg is supposed to be called before "==" comparison.
========================================
Shengqiao Li
Research Associate
The Department of Statistics
PO Box 6330
West Virginia University
Morgantown, WV 26506-6330
2018 Sep 19
4
Bias in R's random integers?
On Wed, 19 Sep 2018 at 13:43, Duncan Murdoch <murdoch.duncan at gmail.com>
wrote:
>
> I think the analyses are correct, but I doubt if a change to the default
> is likely to be accepted as it would make it more difficult to reproduce
> older results.
I'm a bit alarmed by the logic here. Unbiased sampling seems basic for a
statistical language. As a consumer of R I'd
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 Sep 20
1
Bias in R's random integers?
On 09/19/2018 10:03 AM, Ben Bolker wrote:
...
> Balancing backward compatibility and correctness is a tough problem
> here.
I think improvements in the RNG is a situation where backward
compatibility is not really going to be lost, because people can specify
the old generator, they just will not get it by default. My opinion is
that the default needs to generally be the best option
2018 Sep 19
0
Bias in R's random integers?
On 2018-09-19 09:40 AM, David Hugh-Jones wrote:
> On Wed, 19 Sep 2018 at 13:43, Duncan Murdoch <murdoch.duncan at gmail.com>
> wrote:
>
>>
>> I think the analyses are correct, but I doubt if a change to the default
>> is likely to be accepted as it would make it more difficult to reproduce
>> older results.
>
>
> I'm a bit alarmed by the logic
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
2004 Feb 04
0
Job opportunity
I'm pleased to announce that my employer, Becton Dickinson, has an open
position for software implementation in the Matlab and S languages. If
interested, send a cover letter and resume (or CV) to Dr. Richard Moore at
richard_moore at bd.com. If you have questions, contact myself (at
jim_garrett at bd.com) or Dr. Moore.
Below find a position description.
Jim Garrett
Becton Dickinson
2003 Oct 16
2
.Random.seed
I am writing a function for the purposes of a simulation. Due to memory
problems, the function sometimes crashes. In order to get around this
problem, I would like to include to be able to save the "last" seed, so I
can pick up with the next run of the simulation after a "crash". I am
having trouble understanding what is going on with .Random.seed!
For each run of the
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
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
2015 Feb 08
0
Which function can change RNG state?
On 7 February 2015 at 19:52, otoomet wrote:
| random numbers. For instance, can I be sure that
| set.seed(0); print(runif(1)); print(rnorm(1))
| will always print the same numbers, also in the future version of R? There
Yes, pretty much.
I've been lurking here over fifteen years, and while I am getting old and
forgetful I can remember exactly one such change where behaviour was changed,
2004 Dec 10
0
strange gee behavior
I'm using R 1.9.1 on suse server v9 enterprise with the gee package version
4.13-10.
I have code that runs in an automated script. It uses the gee function from
the gee package. The script is run quite often without error.
I have a problem where the script locks up R when calling this function (it
starts execution and never finishes). I was able to track down the
offending data and determine
1999 Jun 12
0
Random numbers
Hi,
I have a few questions about the RNG in R; apologies if these are dumb
questions:
1. It is my understanding that, among the three types of random number
generators available in R now, the best one is the Marsaglia Multicarry. Is
this correct?
2. How does the best RNG in R compare (in terms of quality) to the RNG in
SPlus? (based on Marsaglia's Super Duper)? Does the Super-Duper in
2023 Feb 16
0
User-defined RNG with the standalone Rmath library
I have two questions about using a user-defined random number generator (RNG) with the standalone Rmath library. The default RNG with the standalone Rmath library is the Marsaglia-multicarry generator, which has poor properties. The "R Installation and Administration" manual, in the section "The standalone Rmath library", states that:
```
A little care is needed to use the
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
>