6 messages · Arne.Muller@aventis.com, Roger D. Peng, Bob Wheeler +2 more
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
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
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
______________________________________________ R-help at stat.math.ethz.ch 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
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
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 Arne.Muller at aventis.com 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
______________________________________________ R-help at stat.math.ethz.ch 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
______________________________________________ R-help at stat.math.ethz.ch 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.
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 Arne.Muller at aventis.com 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
______________________________________________ R-help at stat.math.ethz.ch 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
______________________________________________ R-help at stat.math.ethz.ch 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
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.
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, ripley at stats.ox.ac.uk 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, UK Fax: +44 1865 272595
Note R-patched and R-devel get more accurate answers.
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 Arne.Muller at aventis.com 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
______________________________________________ R-help at stat.math.ethz.ch 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
______________________________________________ R-help at stat.math.ethz.ch 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
______________________________________________ R-help at stat.math.ethz.ch 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, ripley at stats.ox.ac.uk 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, UK Fax: +44 1865 272595