[R] number point under-flow
Hello, I've come across the following situation in R-1.8.1 (compile + running under RedHat 7.1): phyper(24, 514, 5961-514, 53, lower.tail=T) [1] 1 phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -1.037310e-11 I'd expect the later to be 0 or some very small positive number. Is this a number under-flow of the calculation? Do you think I'm safe if I just set the result to 0 in these cases? kind regards, Arne __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] number point under-flow
Did you compile with gcc-2.96? I think there were some problems with the floating point arithmetic with that compiler (at least for the earlier versions released by Red Hat). -roger [EMAIL PROTECTED] wrote: Hello, I've come across the following situation in R-1.8.1 (compile + running under RedHat 7.1): phyper(24, 514, 5961-514, 53, lower.tail=T) [1] 1 phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -1.037310e-11 I'd expect the later to be 0 or some very small positive number. Is this a number under-flow of the calculation? Do you think I'm safe if I just set the result to 0 in these cases? kind regards, Arne __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
RE: [R] number point under-flow
Hi, yes, I did compile it with gcc 2.96 ... . Do you've an estimate on how bad this error is, e.g. how much it effects the calculations in R? kind regards, Arne -Original Message- From: Roger D. Peng [mailto:[EMAIL PROTECTED] Sent: 04 February 2004 14:49 To: Muller, Arne PH/FR Cc: [EMAIL PROTECTED] Subject: Re: [R] number point under-flow Did you compile with gcc-2.96? I think there were some problems with the floating point arithmetic with that compiler (at least for the earlier versions released by Red Hat). -roger [EMAIL PROTECTED] wrote: Hello, I've come across the following situation in R-1.8.1 (compile + running under RedHat 7.1): phyper(24, 514, 5961-514, 53, lower.tail=T) [1] 1 phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -1.037310e-11 I'd expect the later to be 0 or some very small positive number. Is this a number under-flow of the calculation? Do you think I'm safe if I just set the result to 0 in these cases? kind regards, Arne __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] number point under-flow
Roger D. Peng wrote: Did you compile with gcc-2.96? I think there were some problems with the floating point arithmetic with that compiler (at least for the earlier versions released by Red Hat). Not (solely) a gcc-2.96 bug, since we get phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -3.325784e-12 on Windows compiled with gcc-3.3.1 Uwe Ligges -roger [EMAIL PROTECTED] wrote: Hello, I've come across the following situation in R-1.8.1 (compile + running under RedHat 7.1): phyper(24, 514, 5961-514, 53, lower.tail=T) [1] 1 phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -1.037310e-11 I'd expect the later to be 0 or some very small positive number. Is this a number under-flow of the calculation? Do you think I'm safe if I just set the result to 0 in these cases? kind regards, Arne __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] number point under-flow
It's not the compiler. pghyper() in SuppDists does the same thing. Its just rounding error. Set the result to 0 if it bothers you. pghyper(24,514,53, 5961, lower.tail=F) [1] -3.325965e-12 Roger D. Peng wrote: Did you compile with gcc-2.96? I think there were some problems with the floating point arithmetic with that compiler (at least for the earlier versions released by Red Hat). -roger [EMAIL PROTECTED] wrote: Hello, I've come across the following situation in R-1.8.1 (compile + running under RedHat 7.1): phyper(24, 514, 5961-514, 53, lower.tail=T) [1] 1 phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -1.037310e-11 I'd expect the later to be 0 or some very small positive number. Is this a number under-flow of the calculation? Do you think I'm safe if I just set the result to 0 in these cases? kind regards, Arne __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html -- Bob Wheeler --- http://www.bobwheeler.com/ ECHIP, Inc. --- Randomness comes in bunches. __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] number point under-flow
Try the latest patched version, as this has already been fixed. phyper(24, 514, 5961-514, 53, lower.tail=F) [1] 1.084688e-13 o [l]choose() use a more accurate formula which also slightly improves p- and qhyper(); choose(n, k) now returns 0 instead of NaN for k 0 or n. On Wed, 4 Feb 2004 [EMAIL PROTECTED] wrote: Hello, I've come across the following situation in R-1.8.1 (compile + running under RedHat 7.1): phyper(24, 514, 5961-514, 53, lower.tail=T) [1] 1 phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -1.037310e-11 I'd expect the later to be 0 or some very small positive number. Is this a number under-flow of the calculation? Do you think I'm safe if I just set the result to 0 in these cases? -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UKFax: +44 1865 272595 __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] number point under-flow
Note R-patched and R-devel get more accurate answers. On Wed, 4 Feb 2004, Uwe Ligges wrote: Roger D. Peng wrote: Did you compile with gcc-2.96? I think there were some problems with the floating point arithmetic with that compiler (at least for the earlier versions released by Red Hat). Not (solely) a gcc-2.96 bug, since we get phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -3.325784e-12 on Windows compiled with gcc-3.3.1 Uwe Ligges -roger [EMAIL PROTECTED] wrote: Hello, I've come across the following situation in R-1.8.1 (compile + running under RedHat 7.1): phyper(24, 514, 5961-514, 53, lower.tail=T) [1] 1 phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -1.037310e-11 I'd expect the later to be 0 or some very small positive number. Is this a number under-flow of the calculation? Do you think I'm safe if I just set the result to 0 in these cases? kind regards, Arne __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UKFax: +44 1865 272595 __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
