From: Mike Stok Date: 2010-04-02T06:21:03+09:00 Subject: Re: Is there a method to set variable to NaN or Infinity? On Apr 1, 2010, at 3:48 PM, Colin Bartlett wrote: > On Thu, Apr 1, 2010 at 3:57 PM, Alex DeCaria > wrote: >> Is there a built-in method to set a floating point value to NaN or >> Infinity? Or, is the only way to do this by >> a = 0.0/0.0 # set a to NaN >> b = 3.0/0.0 # set b to Infinity >> c = -3.0/0.0 # set c to -Infinity > > In the past I have done something like: > Float::NaN = 0.0 / 0.0 #=> NaN > Float::Infinity = 3.0 / 1.0 #=> Infinity That's a pretty small infinity :-) Mike > -Float::Infinity #=> -Infinity > In other words, do they have to be methods? Can they just be constants? > (But I think it might be useful to have those constants automatically in Float?) > >> Also, how can I set value to -NaN? This is possible in other languages, >> but I can't do it in Ruby. I've tried: >> a = 0.0/0.0 >> b = -a >> but b still comes out NaN. > > I'm curious: which languages have a -NaN value and why would you want > to use it instead of just NaN? > I've just tried Octave, and in that > n = 0.0 / 0.0 #=> NaN > nn = -n #=> NaN > so I assume that there isn't a "-NaN" in Octave, although as Nan == > NaN returns 0 (false) > I'd need to look at the documentation to be sure. > > Colin Bartlett > -- Mike Stok http://www.stok.ca/~mike/ The "`Stok' disclaimers" apply.