From: Uwe Ligges <ligges_at_statistik.uni-dortmund.de>

Date: Fri 17 Feb 2006 - 08:17:17 EST

*>
*

*>
*

*> In R:
*

*>
*

*> x<-rep(0.02,10)
*

> var(x)

> 1.337451e-35

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Feb 17 08:56:43 2006

Date: Fri 17 Feb 2006 - 08:17:17 EST

Barry Zajdlik wrote:

> Hi All,

*>
**> An annoying but not critical problem I am having is that the variance of
**> a vector of constants is reported as > 0. I imagine there is a simple
**> workaround for the following but could not find it after having spent an
**> embarrassing amount of time.
**>
**> In Splus:
**>
**>
*

>>x<-rep(0.02,10) >>var(x) >>0

> var(x)

> 1.337451e-35

Which version of R and which OS is this? I get 0 for both Linux and
Windows with R-2.2.1.

Anyway, 0.02 is not well representable and hence can be very well the
cause for such a numerical inaccuracy.

> I assumed the problem had to do with machine precision and suitably

*> modified .Machine$double.eps and .Machine$double.neg.eps which I thought
**> would fix the problem but without success. Any pointers to a solution
**> would be appreciated!
*

Changing .Machine$double.eps does not help to calculate more accurate ...

Uwe Ligges

*> Cheers,
**> Barry Zajdlik
**>
*

> ______________________________________________

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R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Feb 17 08:56:43 2006

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