similar to: Re: [R] Bug in qchisq? (PR#875)

Kenneth Cabrera <krcabrer@epm.net.co> writes: > Hello developers and users: > > My system fails (the computer freezes) when I use the ncp parameter, > with the lower.tail=FALSE option in the qchisq function. > > qchisq(0.025,31,ncp=1,lower.tail=FALSE) Yup, that's a bug. We have in pnchisq.c 48 for (ux = 1.0; pnchisq(ux, n, lambda, lower_tail, log_p) <

Hello developers and users: My system fails (the computer freezes) when I use the ncp parameter, with the lower.tail=FALSE option in the qchisq function. qchisq(0.025,31,ncp=1,lower.tail=FALSE) Thank you very much for your help. Kenneth Cabrera Universidad Nacional de Colombia ICNE Sede Medellin krcabrer at perseus.unalmed.edu.co PS I am using: $platform "i386-pc-mingw32"

Full_Name: Drouilhet R?my Version: 1.8.1 OS: Linux Submission from: (NULL) (195.221.43.136) qchisq(1,10) works well but qchisq(1,10,ncp=0) does not work whereas ncp=0 is the default value of the function qchisq(1,10). (of course, 10 will be replaced by any integer value). Let us notice that this bug occurs only when applying probability one. (qchisq(seq(0,.9,.1),10,ncp=0) works very well).

Full_Name: David Clayton Version: 1.8.1 OS: Linux Submission from: (NULL) (131.111.126.242) qchisq behaves very strangely when ncp is passed as zero (forcing internal qnchisq to be called) when first argument is small. Eg > qchisq(1-1e-6, 1, ncp=0, lower.tail=TRUE) qchisq(1-1e-6, 1, ncp=0, lower.tail=TRUE) [1] 1024 while, if ncp is unspecified, > qchisq(1-1e-6, 1) qchisq(1-1e-6, 1)

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

Full_Name: Morten Welinder Version: 2.1.0 OS: src only Submission from: (NULL) (216.223.241.212) Now that pcauchy has been fixed, it is becoming clear that qcauchy suffers from the same problems. qcauchy(pcauchy(1e100,0,1,FALSE,TRUE),0,1,FALSE,TRUE) should yield 1e100 back, but I get 1.633178e+16. The code below does much better. Notes: 1. p need not be finite. -Inf is ok in the log_p

Full_Name: Morten Welinder Version: snapshot OS: Submission from: (NULL) (65.213.85.218) Time to kick phyper's tires... The current version has very serious cancellation issues. For example, if you ask for a small right-tail you are likely to get total cancellation. For example phyper(59, 150, 150, 60, FALSE, FALSE) gives 6.372680161e-14. The right answer is dhyper(0, 150, 150, 60,

Full_Name: Morten Welinder Version: 1.5.1 OS: Solaris Submission from: (NULL) (65.213.85.136) I was having problems with qgamma's precision in the sense that pgamma(qpgamma(x)) was not as close to the identity function as I would like. I was seeing relative errors with random input of about 1e-8. This fits nicely with the code'd EPS2 value of 5e-7. To solve this I added a newton step

Hi R users: Thank you very much for you help, you are very kind. I am again asking for your help to make a function that returns the numbers of elements of each category given in another vector. I mean, I have a vector "x" with several elements (most of them more that once) and other vector "y" with the elements that I want to count in the first vector (is not a exhaustive

Hi R users: I want to know how can I easily sort in descending order a whole data frame by one or several variables. Thank you very much for your help. Kenneth Cabrera krcabrer at perseus.unalmed.edu.co krcabrer at epm.net.co Universidad Nacional de Colombia, Sede Medell?n -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read

Full_Name: M. Welinder Version: 1.8.1 OS: Solaris Submission from: (NULL) (65.213.85.227) Currently R has... #define R_D_Lval(p) (lower_tail ? (p) : (1 - (p))) /* p */ #define R_D_val(x) (log_p ? log(x) : (x)) /* x in pF(x,..) */ #define R_DT_val(x) R_D_val(R_D_Lval(x)) /* x in pF */ ...which is sub-optimal in the lower_tail==FALSE && log_p==TRUE case. Something like this ought

Full_Name: Mikael Weigelt Version: 2.0 OS: windows Submission from: (NULL) (207.171.180.101) The calculation of the qpois attempts to use the Cornish-Fisher expansion as a starting approximation. The definition of the expansion is incorrect. However, since this approximation just gives an initial solution, the end result of the function is still correct. To fix the approximation, in the

>>>>> Constantin Ahlmann-Eltze via R-devel >>>>> on Mon, 10 Aug 2020 10:05:36 +0200 writes: > Thanks Ben for verifying the issue. It is always reassuring to hear > when others can reproduce the problem. > I wrote a small patch that fixes the issue > (https://github.com/r-devel/r-svn/pull/11): > diff --git

Hi Martin, thanks for verifying. I agree that the Cornish-Fisher seems to struggle with the small size parameters, but I also don't have a good idea how to replace it. But I think fixing do_search() is possible: I think the problem is that when searching to the left y is decremented only if `pnbinom(y - incr, n, pr, /*l._t.*/TRUE, /*log_p*/FALSE)) < p` is FALSE. I think the solution is

Full_Name: Alan Bain Version: 2.4.0 OS: XP Submission from: (NULL) (155.140.122.227) Code for pnchisq contains following if (tSml) { if (x> f+ theta+ 5*sqrt(2*(f+2*theta) ))){ return 1.; /* better than 0 --- but definately FIXME */ } } This needs to check which tail has been requested; it is only correct if the default lower_tail=1 has been requested; for upper tail should return 0

Hello all, Here's my query: Running R 1.6.2 on FreeBSD 5.0, and on WinXP, and I find that the following hangs the process: dchisq(alpha=0.01, df=1, ncp=295) but it does work for ncp < 294.92. Is this general? Best wishes to all, Andrew Andrew Robinson Ph: 208 885 7115 Department of Forest Resources Fa: 208 885 6226 University of Idaho E : andrewr at uidaho.edu PO

Thanks Ben for verifying the issue. It is always reassuring to hear when others can reproduce the problem. I wrote a small patch that fixes the issue (https://github.com/r-devel/r-svn/pull/11): diff --git a/src/nmath/qnbinom.c b/src/nmath/qnbinom.c index b313ce56b2..d2e8d98759 100644 --- a/src/nmath/qnbinom.c +++ b/src/nmath/qnbinom.c @@ -104,6 +104,7 @@ double qnbinom(double p, double size,

Hello everybody: Does any one has a function to build Chernoff faces? Thank you very much Kenneth Roy Cabrera Torres krcabrer at epm.net.co -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not

Full_Name: M Welinder Version: 1.4 OS: (src) Submission from: (NULL) (192.5.35.38) It seems to me that pweibull can be improved in the lower_tail=TRUE and log_p=FALSE case by using expm1. Something like -expm1(-pow(x / scale, shape)), I think. -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read

Full_Name: Jerry W. Lewis Version: 2.6.1 OS: Windows XP Professional Submission from: (NULL) (24.147.191.250) pchisq(0,0,ncp=lambda) returns 0 instead of exp(-lambda/2) pchisq(x,0,ncp=lambda) returns NaN instead of exp(-lambda/2)*(1 + SUM_{r=0}^infty ((lambda/2)^r / r!) pchisq(x, df + 2r)) qchisq(.7,0,ncp=1) returns 1.712252 instead of 0.701297103 qchisq(exp(-1/2),0,ncp=1) returns 1.238938