r - Why does NaN^0 == 1 -


prompted spot of earlier code golfing why would:

>nan^0 [1] 1

it makes perfect sense na^0 1 because na missing data, , any number raised 0 give 1, including -inf , inf. nan supposed represent not-a-number, why so? more confusing/worrying when page ?nan states:

in r, mathematical functions (including basic arithmetic), supposed work +/- inf , nan input or output.

the basic rule should calls , relations infs statements proper mathematical limit.

computations involving nan return nan or perhaps na: of 2 not guaranteed , may depend on r platform (since compilers may re-order computations).

is there philosophical reason behind this, or how r represents these constants?

this referenced in page referenced ?'nan'

"the iec 60559 standard, known ansi/ieee 754 floating-point standard.

http://en.wikipedia.org/wiki/nan."

and there find statement regarding should create nan:

 "there 3 kinds of operations can return nan:[5]        operations nan @ least 1 operand.

it particular c compiler, signified note referenced. gnu c documentation says:

http://www.gnu.org/software/libc/manual/html_node/infinity-and-nan.html

" nan, on other hand, infects calculation involves it. unless calculation produce same result no matter real value replaced nan, result nan."

so seems gnu-c people have different standard in mind when writing code. , 2008 version of ansi/ieee 754 floating-point standard reported make suggestion:

http://en.wikipedia.org/wiki/nan#function_definition

the published standard not free. if have access rights or money can here:

http://ieeexplore.ieee.org/xpl/mostrecentissue.jsp?punumber=4610933


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