[R] Odp: calculate differences - strange outcome

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 17.07.2008 11:47:42:

> Dear List,
> 
> I ran into some trouble by calculating differences. For me it is
> important that differences are either 0 or not.

So you shall not use computers. They do not work with infinite precision.
See Faq 7.31

Regards
Petr

> 
> So I don't understand the outcome of this calculation
> 
> 865.56-(782.86+0+63.85+18.85+0)
> [1] -1.136868e-13
> 
> I run R version 2.71 on WinXP
> 
> I could solve my problem by using
> round()
> but I would like to know the reason.
> Maybe someone can help me?
> 
> Thanx
> 
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