Displaying 20 results from an estimated 4000 matches similar to: "pt inaccurate when x is close to 0 (PR#9945)"
2007 Oct 03
1
accuracy of pt for x close to 0
Hello,
I have been playing around with the statistical distributions in R, and
overall I think the accuracy is very good. However, it seems that for the
Student's t distribution, the CDF loses accuracy when evaluated at values
close to zero. For instance, I did the following in R
----------------------------------
df<-seq(1,100,by=1)
2008 Feb 15
1
pt inaccurate when x is close to 0 (PR#9945)
While I agree that the reported results from Mathematica have only 10-13
correct digits, that does not mean that pt() in R is any better for these
calculations. For instance the following three calculations are
mathematically equivalent, but pt() disagrees at the 13th figure in R
v2.6.2
pt(1e-4,13)
pf(1e-8,1,13)/2+0.5
pbeta(1/(1+13/1e-8),.5,6.5)/2+0.5
Using 1/(1+n/x^2) and reversing the
2007 Oct 11
1
[Fwd: Re: pt inaccurate when x is close to 0 (PR#9945)]
Here's a contribution from Ian Smith that got bounced from the list.
-------- Original Message --------
Subject: Re: [Rd] pt inaccurate when x is close to 0 (PR#9945)
Date: Thu, 11 Oct 2007 06:02:43 -0400
From: iandjmsmith at aol.com
To: murdoch at stats.uwo.ca
Duncan,
I tried sending the rest of this to R-devel but it was rejected as spam,
hence the personal e-mail.
R calculates the pt
2008 Aug 05
1
optimize simultaneously two binomials inequalities using nlm( ) or optim( )
Dear R users,
I?m trying to optimize simultaneously two binomials inequalities (used in
acceptance sampling) which are nonlinear solution, so there is no simple
direct solution. Please, let me explain shortly the the problem and the
question as following.
The objective is to obtain the smallest value of 'n' (sample size)
satisfying both inequalities:
(1-alpha) <= pbinom(c, n, p1)
2012 Sep 17
1
other files in \inst\doc
I would like to include a Mathematica notebook and cdf file (both are
ASCII files) in the \inst\doc directory as supporting documentation. These
files are not large, about 340K each one. When I check using
R CMD check --as-cran ...
I get the following warning:
......................
* checking data for ASCII and uncompressed saves ... OK
WARNING
'qpdf' is needed for checks on size
2016 Dec 18
0
llvm (the middle-end) is getting slower, December edition
On Sat, Dec 17, 2016 at 1:35 PM, Davide Italiano <davide at freebsd.org> wrote:
[...]
> I don't have an infrastructure to measure the runtime performance
> benefits/regression of clang, but I have for `game7`.
> I wasn't able to notice any fundamental speedup (at least, not
> something that justifies a 2x build-time).
>
Just to provide numbers (using Sean's
2016 Dec 18
0
llvm (the middle-end) is getting slower, December edition
On Dec 17, 2016 7:41 PM, "Sean Silva" <chisophugis at gmail.com> wrote:
On Sat, Dec 17, 2016 at 6:32 PM, Davide Italiano via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> On Sat, Dec 17, 2016 at 1:35 PM, Davide Italiano <davide at freebsd.org>
> wrote:
> [...]
>
> > I don't have an infrastructure to measure the runtime performance
> >
2008 Aug 07
1
qgamma inaccuracy (PR#12324)
Full_Name:
Version: 2.7.1 (2008-06-23)
OS: windows vista
Submission from: (NULL) (216.82.144.137)
Hello,
I have been working with various probability distributions in R, and it seems
the gamma distribution is inaccurate for some inputs.
For example, qgamma(1e-100, 5e-101, lower.tail=FALSE) gives: 1.0. However, it
seems this is incorrect; I think the correct answer should be
2008 Jul 21
0
optimize function help!!
Dear R users,
I?m trying to optimize simultaneously two binomials inequalities used to
acceptance sampling, which are nonlinear solution, so there is no simple
direct solution.
The 'n' represents the sample size and the 'c' an acceptance number or
maximum number of defects (nonconforming) in sample size.
The objective is to obtain the smallest value of 'n' (sample size)
2004 Mar 19
3
Incomplete Gamma Functions and GammaDistribution Doc errata.
Hello all,
In the course of trying to implement the CDF of an
InverseGammaDistribution, I have run across the need for an igamma()
function. Several others have needed this function but the answers I
have found so far are not totally clear to me. I'm writing for three
reasons:
1) to present a small error in the docs
2) to clarify the approach we are expected to take
3) to request,for the
2008 Jul 29
0
optimize simultaneously two binomials inequalities using nlm
Dear R users,
I?m trying to optimize simultaneously two binomials inequalities used to
acceptance sampling, which are nonlinear solution, so there is no simple
direct solution. Please, let me explain shortly the the problem and the
question as following.
The objective is to obtain the smallest value of 'n' (sample size)
satisfying both inequalities:
(1-alpha) <= pbinom(c, n, p1)
2007 Jul 11
1
RPM Build Question
Hi People,
I have just started building my own RPMS on both Fedora and CentOS and
generally things have gone well. Currently I am trying to create RPMS
for some commercial software that we have purchased.
Step 1 was install the software using its JAVA Based installer
ensuring that all files were installed into a particular directory in
/usr/local.
Step 2 was create a tar file of the
2008 Mar 06
1
Interesting remarks about R back in 1999
Hi, this is not an R-help post, but I found this extract below that was
written by a leading mathematician back in 1999 when he was talking about
statistics and computing. I found it interesting to share and I ask your
opinion do you think this still holds today or things have changed? Thanks.
?...we would also like to mention that in our opinion Mathematica provides
an excellent and indeed
2010 Jul 14
3
Mathematica and R
What are some effective ways to leverage the strengths of R and
Mathematica for the analysis of a single data set?
More specifically, are there any functions that can assist with any of
the following?
1. Calling an R function from Mathematica.
2. Calling a Mathematica function from R.
3. Using XML or another reliable data format to pass vectors, matrices,
and/or lists from one environment to
2006 Sep 01
1
integration problem with gamma function
Dear R-list members,
I have a problem with translating a mathematica script into R. The whole
script is at the end of the email (with initial values for easy
reproduction) and can be pasted directly into R. The problematic part
(which is included below of course) is
<--- Original Mathematica --->
(* p_svbar *)
UiA = Ni (Dsi - 2Di A + A^2)/2;
UiiA = Nii (Dsii - 2Dii A + A^2)/2;
psvbar =
2007 Jul 10
3
ECDF, distribution of Pareto, distribution of Normal
Hello all,
I would like to plot the emperical CDF, normal CDF and pareto CDF in the
same graph and I amusing the following codes. "z" is a vector and I just
need the part when z between 1.6 and 3.
plot(ecdf(z), do.points=FALSE, verticals=TRUE,
xlim=c(1.6,3),ylim=c(1-sum(z>1.6)/length(z), 1))
x <- seq(1.6, 3, 0.1)
lines(x,pgpd(x, 1.544,0.4373,-0.2398), col="red")
y
2007 Jun 22
3
How to run "mathematica" or "c" programs in R?
I have some programs which were writen in mathematica or c language, but I
donot know how to use these software. So I want to run them in R.
Can I do it ?
How to run "mathematica" or "c" programs in R?
Jian Zhang
[[alternative HTML version deleted]]
2010 Feb 09
1
how to adjust the output
Hi R-users,
I have this code below and I understand the error message but do not know how to correct it. My question is how do I get rid of “with absolute error < 7.5e-06” attach to value of cdf so that I can carry out the calculation.
integrand <- function(z)
{ alp <- 2.0165
rho <- 0.868
# simplified expressions
a <- alp-0.5
c1 <-
2012 Mar 08
1
Doing Mathematica Quantile[] function in R
Hi all,
I am an R newbie trying to do some calculations I do in Mathematica in
R on a GNU/Linux system.
The main thing I am interested in doing is taking a 0.999 quantile on
a data set in a file who's data is normally distributed, say foo.csv.
e.g in Mathematica if I have something like this :
a=Import["foo.csv"]
b=Transpose[a][[1]]
Quantile[b,0.999]
In R I can load all the data
2007 Sep 12
1
Integrate() error message, I am at a loss
Hello!
I have a problem with integrate() in my function nctspa(). Integrate
produces an error message "evaluation of function gave a result of
wrong length". I don't know what that means. Could anyone suggest me
what is wrong with my function?
These are the examples of function calls that work OK:
nctspa(a=1:10,n=5)
nctspa(a=1:10, n=5, mu=2, theta=3, renorm=0)
This does not work: