On 26/05/2014 13:16, ritwi...@isical.ac.in wrote:
Dear R helpers,
today I found something interesting in R. 0^0 gives value 1 in R. But it
is undefined in mathematics. During debugging a R code, I found it and it
effects my program severely. So my question is why it is defined 1 in R?
Is there any particular reason or its a bug in the R software?
Try reading the help:
Users are sometimes surprised by the value returned, for example
why ‘(-8)^(1/3)’ is ‘NaN’. For double inputs, R makes use of IEC
60559 arithmetic on all platforms, together with the C system
function ‘pow’ for the ‘^’ operator. The relevant standards
define the result in many corner cases. In particular, the result
in the example above is mandated by the C99 standard. On many
Unix-alike systems the command ‘man pow’ gives details of the
values in a large number of corner cases.
See §F9.4.4 of the C99 standard.
Here is one demo:
*************************************************
ff=function(u){
return( x^0 * u)
}
x=0
zz=integrate(ff,lower=0,upper=1)$value
zz
source('~/.active-rstudio-document')
zz
[1] 0.5
*************************************************
Looking forward to hear any response.
Regards,
Ritwik Bhattacharya
Indian Statistical Institute Kolkata
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--
Brian D. Ripley, rip...@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
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and provide commented, minimal, self-contained, reproducible code.
