Hi
Thanks for the quick reply. However, I am not satisfied, as
> round(3.15000000, 1)
[1] 3.1
> round(3.75000000, 1)
[1] 3.8
I think the problem is really more of an error in the rounding off
algorithm than finite precision.
Thanks
Teckpor
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Peter
Dalgaard
Sent: Monday, May 29, 2006 17:49
To: [EMAIL PROTECTED]
Cc: r-devel@stat.math.ethz.ch; [EMAIL PROTECTED]
Subject: Re: [Rd] Numerical error in R (win32) (PR#8909)
[EMAIL PROTECTED] writes:
> Hi
> I had observed the following problem in R (also C, Matlab, and
Python).
> sprintf('%1.2g\n', 3.15)
> give 3.1 instead of 3.2 whereas an input of 3.75 gives 3.8.
> Java's System.out.printf is ok though.
>
> > round(3.75,1)
> [1] 3.8
> > round(3.15,1)
> [1] 3.1
>
> Similar outcome with sprintf in R.
>
>
> However, the right answer should be 3.2
According to what? Remember that we're dealing with finite precision binary
arithmetic here:
> (3.15 - 3.1)<.05
[1] TRUE
> abs(3.15 - 3.2)>.05
[1] TRUE
See also FAQ 7.31.
> Regards
> Teckpor
>
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
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