[R] precision in seq

From: Eric Elguero <Eric.Elguero_at_mpl.ird.fr>
Date: Mon, 4 Feb 2008 13:53:52 +0100

Hi everybody,

this is a warning more than a question.

I noticed that seq produces approximate results:

> seq(0,1,0.05)[19]==0.9

[1] TRUE
> seq(0,1,0.05)[20]==0.95

> seq(0,1,0.05)[21]==1

[1] TRUE
> seq(0,1,0.05)[20]-0.95

[1] 1.110223024625157e-16

I do not understand why 0.9 and 1 are correct (within some tolerance or strictly exact?) and 0.95 is not.

this one works:

> ((0:20)/20)[20]==0.95

[1] TRUE Eric Elguero

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