search for: qbeta

I've discovered an infelicity (I guess) in qbeta(): it's not a bug, since there's a clear warning about lack of convergence of the numerical algorithm ("full precision may not have been achieved"). I can work around this, but I'm curious why it happens and whether there's a better workaround -- it doesn't seem to be...

HI All: Does anyone know the code behind the qbeta function in R? I am using it to calculate exact confidence intervals and I am getting 'NaN' at places I shouldnt be. Heres the simple code I am using: k<-3 > x<-NULL > p<-rbeta(k,3,3)# so that the mean nausea rate is alpha/(alpha+beta) > min<-10 > max<-60 > n&...

>>>>> Ben Bolker >>>>> on Wed, 25 Mar 2020 21:09:16 -0400 writes: > I've discovered an infelicity (I guess) in qbeta(): it's not a bug, > since there's a clear warning about lack of convergence of the numerical > algorithm ("full precision may not have been achieved"). I can work > around this, but I'm curious why it happens and whether there's a better > wor...

Hi there, this is just to let you know that the qbeta function, which was copied from R into Gnumeric, has been confirmed to be miscompiled by gcc 2.96 on Linux. (That's Red Hat's compiler.) This shows by qbeta(0.025,4,0.5) ending up taking the wrong branch of "if (alpha <= 0.5)". We compile things in a different context, so th...

Full_Name: Ziheng Yang Version: 1.3.1 OS: Windows 98 Submission from: (NULL) (172.136.54.89) I noticed that qbeta is sometimes wrong and the error is not even due to the beta parameters being too extreme. I am calculating the quantiles corresponding to cdf = 0.05, 0.15, ..., 0.95. The value corresponding to cdf=0.25 is wrong while all other values are correct. qbeta(0.05, 0.143891, 0.05) = 1.040850e-05...

Given that a number of us are housebound, it might be a good time to try to improve the approximation. It's not an area where I have much expertise, but in looking at the qbeta.c code I see a lot of root-finding, where I do have some background. However, I'm very reluctant to work alone on this, and will ask interested others to email off-list. If there are others, I'll report back. Ben: Do you have an idea of parameter region where approximation is poor? I think...

I need to run qbeta on a set of 500K different parameter pairs (with a fixed quantile). For most pairs qbeta finds the solution very quickly but for a substantial minority of the cases qbeta is very slow. This occurs when the solution is very close to zero. qbeta is getting answers to a precision of about 16 decimal p...

...rofiling Recommended packages: yes 44 (0) $ make [...] 45 (0) $ make check [...] running code in 'd-p-q-r-tests.R' ... OK comparing 'd-p-q-r-tests.Rout' to './d-p-q-r-tests.Rout.save' ...777,778d776 < Warning message: < full precision was not achieved in 'qbeta' make[3]: *** [d-p-q-r-tests.Rout] Error 1 [...] 46 (0) $ diff tests/d-p-q-r-tests.Rout.{save,fail} 3c3 < Version 2.3.0 alpha (2006-04-03 r37628) --- > Version 2.3.0 alpha (2006-04-08 r37675) 791a792,793 > Warning message: > full precision was not achieved in 'qbeta' 1073...

Full_Name: Morten Welinder Version: 1.6.1 OS: Solaris/sparc Submission from: (NULL) (65.213.85.144) qbeta(0.1, 1e-8, 0.5, TRUE, FALSE) seems to hang for me.

...ash >>>>>> on Thu, 26 Mar 2020 09:29:53 -0400 writes: > > > Given that a number of us are housebound, it might be a good time to try to > > improve the approximation. It's not an area where I have much expertise, but in > > looking at the qbeta.c code I see a lot of root-finding, where I do have some > > background. However, I'm very reluctant to work alone on this, and will ask > > interested others to email off-list. If there are others, I'll report back. > > Hi John. > Yes, qbeta() {in its "ma...

This is also strange: qbeta <- function (p, shape1, shape2, ncp = 0, lower.tail = TRUE, log.p = FALSE) { if (missing(ncp)) .Call(C_qbeta, p, shape1, shape2, lower.tail, log.p) else .Call(C_qnbeta, p, shape1, shape2, ncp, lower.tail, log.p) } Since the default value is 0 for non-centrality, it se...

...Logit Normal > p<-exp(eta)/(1+exp(eta)) > for(i in 1:k) > x<-cbind(x,rbinom(10,n,p[i])) > > rate<-t(t(x)/n) > > # Exact Confidence Interval > > for (i in 1:10){ > > for (j in 1:63) > { > > if (x==0) > { > l_cl_exact<-0 > u_cl_exact<-qbeta(.975,x+1,n-x) > } > else if (x==n) > { > l_cl_exact<-qbeta(.025,x,n-x+1) > u_cl_exact<-1 > } > else > l_cl_exact<-qbeta(.025,x,n-x+1) > u_cl_exact<-qbeta(.975,x+1,n-x) > > } > }_____________________________________________ > R-help@r-project.org ma...

...t;>>>> J C Nash >>>>> on Thu, 26 Mar 2020 09:29:53 -0400 writes: > Given that a number of us are housebound, it might be a good time to try to > improve the approximation. It's not an area where I have much expertise, but in > looking at the qbeta.c code I see a lot of root-finding, where I do have some > background. However, I'm very reluctant to work alone on this, and will ask > interested others to email off-list. If there are others, I'll report back. Hi John. Yes, qbeta() {in its "main branches"} does...

Hi, I sometimes play around with extreme parameters for distributions and found that qbeta is not always monotone as the following example shows. I don't know whether this is serious enough to submit a bug report (as this example is near to the limitations of floating point arithmetic). Josef > x <- qbeta((0:100)/100,0.01,5) > x [1] 0.000000e+00 1.253990e-201 1.589622e-...

>Date: Fri, 2 May 2003 10:03:23 -0400 (EDT) From: Morten Welinder <welinder@rentec.com> >To: p.dalgaard@biostat.ku.dk >CC: r-devel@stat.math.ethz.ch, R-bugs@biostat.ku.dk >Subject: Re: [Rd] qbeta hang (PR#2894) > >Ok, I can confirm that it does not, in fact, loop forever. Just a close >approximation. ... >There are lots of other places that worry me with respect to cancellation >errors, for example > > r = 1 - pp; > t = 1 - qq; These can also be removed by...

Full_Name: Tim Massingham Version: 1.2.2 OS: Debian/Linux Submission from: (NULL) (131.111.8.68) In 1.2.2 sources (also in 0.90.1. I haven't been able to check other versions) Line 103 in qbeta.c should read: w = y * sqrt(h + r) / h - (t - s) * (r + 5. / 6. - 2 / (3 * h)); since otherwise the 5 / 6 will evaluate to zero (I think). The Statlib fortran code uses five / six instead. Cheers, thanks for great software. TimM. -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-....

...and statistical functions. I can thorougly recommend TOMS Algorithm 708 but I believe there are a couple of problems from you point of view. Firstly there may be restrictions on how it may be used and secondly it doesn't come with a corresponding inverse function. You may, of course, feel your qbeta routine would be fine with a better pbeta. CDFLIB includes this algorithm but comes with the warning "However, code from ACM publications is subject to the ACM policy (below)". The inversion function in CDFLIB is not built to the same high standards as A. H. Morris's code for Algorit...

The current development version dies in qbeta() when compiled with egcs -O, egcs 1.0.2 and glibc 2.0.7 (RedHat versions). Since this also kill the F and t distributions, it doesn't exactly do wonders for R's usefulness... Anyone else seeing this or has my setup just gone out of whack? It does look pretty much like a clear compiler bug...

I'm writing a C program and I'd like to include in it some R routine (quantile functions, typically). I found the functions I have to use (qnorm.c qbeta.c ecc) e some include (nmath.h rmath.h ecc). But I can't compile the project, I receive linker error. Somebody can help me? I say, if I want to include qbeta (for example) in a project of mine, what should I do? ___________________________________

...ting library .\../Debug/complex_plugin.lib and object .\../Debug/complex_plugin.exp libRmath.a(mlutils.o) : warning LNK4217: locally defined symbol __iob imported in function _REprintf libRmath.a(dbeta.o) : error LNK2019: unresolved external symbol _log1p referenced in function _dbeta libRmath.a(qbeta.o) : error LNK2019: unresolved external symbol _log1p referenced in function _qbeta libRmath.a(lbeta.o) : error LNK2019: unresolved external symbol _log1p referenced in function _lbeta libRmath.a(toms708.o) : error LNK2001: unresolved external symbol _log1p libRmath.a(qbeta.o) : error LNK2019: u...