From: Carl Johnson <carlj@...>
Date: 2007-10-15T03:20:08+09:00
Subject: Re: Bug: Numeric#divmod calculates wrongly

"Dirk Traulsen" <dirk.traulsen@lypso.de> writes:

> Am 8 Oct 2007 um 19:49 hat Dirk Traulsen geschrieben:
> 
> > Output:
> > =================================================
> > ruby 1.8.6 (2007-03-13 patchlevel 0) [i386-mswin32] 
> . 
> > x.divmod(y)
> > -----------
> > [6, 0.08]
> > [6, 0.00666666666666667]
> > [6, 0.0466666666666667]
> > [6, 0.0766666666666667]
> > [8, 0.00333333333333341]
> > =================================================
> > 
> > As you can see the divisor 7 is wrongly displayed as 6, while the 
> > modulos are correct.
> > 
> 
> 
> 
> The testcode:
> 
> x=[0.58, 0.59, 0.63, 0.66, 0.67]
> y=1/12.0
> 
> z1=x.map {|a| a/y}
> z2=x.map {|a| a.divmod(y).inspect}
> 
> a=[RUBY_VERSION, RUBY_RELEASE_DATE, RUBY_PLATFORM]
> puts "ruby #{a[0]} (#{a[1]}) [#{a[2]}]"
> puts
> print 'x='
> p x
> puts 'y=1/12.0'
> puts
> puts "x/y\n---"
> puts z1
> puts
> puts "x.divmod(y)\n-----------"
> puts z2

Mine has the same problem running on an Athlon64 running on Debian's
AMD64 version of Etch:

ruby 1.8.5 (2006-08-25) [x86_64-linux]

x=[0.58, 0.59, 0.63, 0.66, 0.67]
y=1/12.0

x/y
---
6.96
7.08
7.56
7.92
8.04

x.divmod(y)
-----------
[6, 0.08]
[6, 0.00666666666666667]
[6, 0.0466666666666667]
[6, 0.0766666666666667]
[8, 0.00333333333333341]

-- 
Carl Johnson		carlj@peak.org