From: Robert Dober <robert.dober@...>
Date: 2006-05-25T18:04:08+09:00
Subject: Re: greatest float smaller than 1.0?

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On 5/17/06, polypus <polypus@yahoo.com> wrote:
>
>
> how do i get the greatest float smaller than 1.0?
>
> thanks
>
> --
> Posted via http://www.ruby-forum.com/.
>
>
I agree with the answers that this question is dangerous and meaningless
unless it is not.
Assuming that you know what you need this is one way how the ruby
interpreter can tell you what that number might be (from its point of view)=
,
although it should not exist ;)
You have be warned about all kind of issues I will not repeat them.

Cheers
Robert

------------------------ 8< --------------------------------

#!/usr/bin/env ruby

delta =3D Float::EPSILON

while (y =3D 1.0 - delta) < 1.0 do
    delta /=3D 2.0
    puts "%0.30f %0.30f" % [delta, y]
end
puts "%0.30f %0.30f" % [delta, y]

On my machine I get

robert@roma:~/ruby/tests$ ruby float.rb
0.000000000000000111022302462516 0.999999999999999777955395074969
0.000000000000000055511151231258 0.999999999999999888977697537484
0.000000000000000055511151231258 1.000000000000000000000000000000

you might get something else.
--=20
Deux choses sont infinies : l'univers et la b=EAtise humaine ; en ce qui
concerne l'univers, je n'en ai pas acquis la certitude absolue.

- Albert Einstein

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