Re: sumskipnan(nan) = 0 ?

[gail]

On Sun Sep  9 21:15 , Søren Hauberg  sent:
>> sum(nan) = nan.
>I think you are misunderstanding the meaning of NaN. "NaN" means "Not a 
>Number", so the addition of "a number" and "not a number" is really well 
>defined. That is NaN+1 can't be a number, and hence must be NaN. Your 
>arguments could to some extend work for "NA" (that is "Not Available"), 
>but even then I wouldn't agree with your logic.

The starting point was sumskipnan. If NaN+1=NaN by defintion, that function is
useless.

What do you mean/refer to when you say that NaN+1 is "well defined"?

G.