marcandre	2014-07-11 14:19:33 +0900 (Fri, 11 Jul 2014)

  New Revision: 46780

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=46780

  Log:
    * lib/matrix.rb: Fix sign for cross_product [#9499]

  Modified files:
    trunk/ChangeLog
    trunk/lib/matrix.rb
    trunk/test/matrix/test_vector.rb
Index: ChangeLog
===================================================================
--- ChangeLog	(revision 46779)
+++ ChangeLog	(revision 46780)
@@ -1,3 +1,7 @@ https://github.com/ruby/ruby/blob/trunk/ChangeLog#L1
+Fri Jul 11 14:19:14 2014  Marc-Andre Lafortune  <ruby-core@m...>
+
+	* lib/matrix.rb: Fix sign for cross_product [#9499]
+
 Fri Jul 11 11:11:50 2014  Koichi Sasada  <ko1@a...>
 
 	* benchmark/prepare_so_k_nucleotide.rb: use require_relative.
Index: lib/matrix.rb
===================================================================
--- lib/matrix.rb	(revision 46779)
+++ lib/matrix.rb	(revision 46780)
@@ -1811,9 +1811,9 @@ class Vector https://github.com/ruby/ruby/blob/trunk/lib/matrix.rb#L1811
   #
   def cross_product(v)
     Vector.Raise ErrDimensionMismatch unless size == v.size && v.size == 3
-    Vector[ v[1]*@elements[2] - v[2]*@elements[1],
-            v[2]*@elements[0] - v[0]*@elements[2],
-            v[0]*@elements[1] - v[1]*@elements[0] ]
+    Vector[ v[2]*@elements[1] - v[1]*@elements[2],
+            v[0]*@elements[2] - v[2]*@elements[0],
+            v[1]*@elements[0] - v[0]*@elements[1] ]
   end
 
   #
Index: test/matrix/test_vector.rb
===================================================================
--- test/matrix/test_vector.rb	(revision 46779)
+++ test/matrix/test_vector.rb	(revision 46780)
@@ -146,4 +146,9 @@ class TestVector < Test::Unit::TestCase https://github.com/ruby/ruby/blob/trunk/test/matrix/test_vector.rb#L146
     v = Vector[Rational(1,2), 0]
     assert_equal(0.5, v.norm)
   end
+
+  def test_cross_product
+    v = Vector[1, 0, 0].cross_product Vector[0, 1, 0]
+    assert_equal(Vector[0, 0, 1], v)
+  end
 end

--
ML: ruby-changes@q...
Info: http://www.atdot.net/~ko1/quickml/