In article <3e31a57f@news.povray.org> , Jellby <jel### [at] M-yahoocom>  
wrote:

>
> Unfortunately, POV-Ray is not perfect and there are (as in most computer
> programs) floatin point inaccuracies and rounding errors. That means the
> result is not *exactly* 0, but slightly lower, and you see -0.000. This is
> normal and expected behaviour, if you are testing against 0 you should in
> turn test that abs(y) < tiny_number.

It isn't even a rounding error.  PI can never be represented exactly in any
evaluation (assuming certain properties of PI are indeed true).  So while
symbolically the result 0.0 is correct, numerically that cannot be reached.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

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