From: "Matthias Wächter" <matthias@...>
Date: 2007-09-04T03:05:58+09:00
Subject: Re: wierd floating point output

On 03.09.2007 19:51, dblack@wobblini.net wrote:
> On Tue, 4 Sep 2007, Matthias Wächter wrote:
>> irb(main):002:0> 0.1.to_s
>> => "0.1"
>>
>> I mean, irrespective of wrongly outputting 0.1 as "0.01" using
>> .to_s, it cannot even correctly calculate the number using floating
>> point printf-like string substitution! :(
> 
> Where does it output "0.01"?

*Sigh* -- I should proofread everything.

The sentence should start with "I mean, irrespective of wrongly
outputting 0.1 as "0.1" using .to_s, ..."

What I mean is that any float stored as a IEEE 754 double (64 bit),
like 0.1 with hex notation 0x3FB999999999999A should have a distinct
string representation such that (a==b) == (a.to_s==b.to_s). Note
that the next higher double 0.1+2.0**-56 with hex notation
0x3FB999999999999B has the same .to_s representation, which is not good.

But that is discussed in another thread.

- Matthias