From: sheepman <sheepman@...>
Date: 2005-09-17T23:27:38+09:00
Subject: Re: 5**(-1/2) gives incorrect results under mathn.

Hi, 
The following patch will fix this problem.

Index: lib/mathn.rb
===================================================================
RCS file: /src/ruby/lib/mathn.rb,v
retrieving revision 1.7
diff -1 -u -r1.7 mathn.rb
--- lib/mathn.rb        19 Dec 2003 17:29:06 -0000      1.7
+++ lib/mathn.rb        17 Sep 2005 14:25:04 -0000
@@ -126,2 +126,3 @@
     if other.kind_of?(Rational)
+      other2 = other
       if self < 0
@@ -146,3 +147,3 @@
        if !elm[1].kind_of?(Integer) and elm[1].denominator != 1
-         return Float(self) ** other
+         return Float(self) ** other2
        end
@@ -154,3 +155,3 @@
        if !elm[1].kind_of?(Integer) and elm[1].denominator != 1
-         return Float(self) ** other
+         return Float(self) ** other2
        end

On Sat, 17 Sep 2005 16:46:46 +0900
C Erler <erlercw@gmail.com> wrote:

> With ruby 1.8.1,
> 
> require 'mathn'
> 
> p 5**(1/2)
> p 5**0.5
> p 5**(-1/2)
> p 5**-0.5
> 
> 2.23606797749979
> 2.23606797749979
> 2.23606797749979
> 0.447213595499958
> 
> 


-- 
sheepman / TAMURA Takashi
sheepman@sheepman.sakura.ne.jp http://sheepman.parfait.ne.jp/