[R] Underflow warnings?

Kjetil Kjernsmo kjetil.kjernsmo at astro.uio.no
Sun Feb 13 13:09:59 CET 2000

Dear all,

I'm a bit concerned about underflow problems. Such problems typically
occur when two almost equal numbers are subtracted. I was wondering if R
has any mechanisms for warning users about potential problems, or if any
policy has been developed? 

To check, I just did:
> 1.0000000000000001 - 1
[1] 0
> 1.000000000000001 - 1
[1] 1.110223e-15
> 1.00000000000001 - 1
[1] 9.992007e-15

I guess many users are unaware of the potential problems caused by
underflow (i.e. garbage becoming significant), so perhaps R should issue
a warning?


Kjetil Kjernsmo
Graduate astronomy-student                    Problems worthy of attack
University of Oslo, Norway            Prove their worth by hitting back
E-mail: kjetikj at astro.uio.no                                - Piet Hein
Homepage <URL:http://www.astro.uio.no/~kjetikj/>
Webmaster at skepsis.no 

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