[R] acos(0.5) == pi/3 FALSE

David Barron mothsailor at googlemail.com
Mon Sep 18 23:08:18 CEST 2006

If you had looked at help("==") you would have seen the following:

For numerical and complex values, remember == and != do not allow for
the finite representation of fractions, nor for rounding error. Using
all.equal with identical is almost always preferable.

Then if you had tried

> all.equal(acos(0.5),pi/3)
[1] TRUE

On 18/09/06, Iñaki Murillo Arcos <inaki.murillo at ehu.es> wrote:
> Hello,
>   I don't know if the result of
>   acos(0.5) == pi/3
> is a bug or not. It looks strange to me.
>    Inaki Murillo
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

David Barron
Said Business School
University of Oxford
Park End Street
Oxford OX1 1HP

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