From: Heesob Park <redmine@...>
Date: 2010-08-11T11:44:10+09:00
Subject: [ruby-core:31672] [Bug #3678] CMath.sqrt(1.i) results to 0.0+0.0i

Bug #3678: CMath.sqrt(1.i) results to 0.0+0.0i
http://redmine.ruby-lang.org/issues/show/3678

Author: Heesob Park
Status: Open, Priority: Normal
Category: lib, Target version: 1.9.x
ruby -v: ruby 1.9.3dev (2010-08-10 trunk 28955) [i386-mswin32_90]

CMath.sqrt(1.i) should be equal to CMath.sqrt(1.0.i)

But CMath.sqrt(1.i) gives wrong result.

C:\>ruby -rcmath -e "p CMath.sqrt(1.i)"
(0.0+0.0i)

C:\>ruby -rcmath -e "p CMath.sqrt(1.0.i)"
(0.7071067811865476+0.7071067811865476i)

Here is the patch
--- cmath.rb    2010-08-11 11:30:07.087219552 +0900
+++ cmath.rb.new        2010-08-11 11:31:14.647214876 +0900
@@ -79,7 +79,7 @@
       else
        r = z.abs
        x = z.real
-       Complex(sqrt!((r + x) / 2), sqrt!((r - x) / 2))
+       Complex(sqrt!((r + x) / 2.0), sqrt!((r - x) / 2.0))
       end
     end
   end


----------------------------------------
http://redmine.ruby-lang.org