marcandre	2014-11-20 02:32:58 +0900 (Thu, 20 Nov 2014)

  New Revision: 48505

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=48505

  Log:
    * lib/matrix.rb: Add Vector#angle_with
      Patch by Egunov Dmitriy [#10442]

  Modified files:
    trunk/ChangeLog
    trunk/NEWS
    trunk/lib/matrix.rb
    trunk/test/matrix/test_vector.rb
Index: ChangeLog
===================================================================
--- ChangeLog	(revision 48504)
+++ ChangeLog	(revision 48505)
@@ -1,3 +1,8 @@ https://github.com/ruby/ruby/blob/trunk/ChangeLog#L1
+Thu Nov 20 02:32:34 2014  Marc-Andre Lafortune  <ruby-core@m...>
+
+	* lib/matrix.rb: Add Vector#angle_with
+	  Patch by Egunov Dmitriy [#10442]
+
 Thu Nov 20 02:10:31 2014  Nobuyoshi Nakada  <nobu@r...>
 
 	* parse.y (ripper_flush_string_content, parser_parse_string):
Index: lib/matrix.rb
===================================================================
--- lib/matrix.rb	(revision 48504)
+++ lib/matrix.rb	(revision 48505)
@@ -1699,6 +1699,7 @@ end https://github.com/ruby/ruby/blob/trunk/lib/matrix.rb#L1699
 # * #-@
 #
 # Vector functions:
+# * #angle_with(v)
 # * #inner_product(v), dot(v)
 # * #cross_product(v), cross(v)
 # * #collect
@@ -2038,6 +2039,20 @@ class Vector https://github.com/ruby/ruby/blob/trunk/lib/matrix.rb#L2039
     self / n
   end
 
+  #
+  # Returns an angle with another vector. Result is within the [0...Math::PI].
+  #   Vector[1,0].angle_with(Vector[0,1])
+  #   # => Math::PI / 2
+  #
+  def angle_with(v)
+    raise TypeError, "Expected a Vector, got a #{v.class}" unless v.is_a?(Vector)
+    Vector.Raise ErrDimensionMismatch if size != v.size
+    prod = magnitude * v.magnitude
+    raise ZeroVectorError, "Can't get angle of zero vector" if prod == 0
+
+    Math.acos( inner_product(v) / prod )
+  end
+
   #--
   # CONVERTING
   #++
Index: NEWS
===================================================================
--- NEWS	(revision 48504)
+++ NEWS	(revision 48505)
@@ -172,6 +172,7 @@ with all sufficient information, see the https://github.com/ruby/ruby/blob/trunk/NEWS#L172
     * Unary - and + added for Vector and Matrix.
     * Vector#cross_product generalized to arbitrary dimensions.
     * Vector#dot and #cross are aliases for #inner_product and #cross_product.
+    * Vector#angle_with returns the angle with its argument
 
 * Pathname
   * Pathname#/ is aliased to Pathname#+.
Index: test/matrix/test_vector.rb
===================================================================
--- test/matrix/test_vector.rb	(revision 48504)
+++ test/matrix/test_vector.rb	(revision 48505)
@@ -182,4 +182,15 @@ class TestVector < Test::Unit::TestCase https://github.com/ruby/ruby/blob/trunk/test/matrix/test_vector.rb#L182
     assert_raise(ArgumentError) { Vector[1, 2].cross_product(Vector[2, -1]) }
     assert_raise(Vector::ErrOperationNotDefined) { Vector[1].cross_product }
   end
+
+  def test_angle_with
+    assert_in_epsilon(Math::PI, Vector[1, 0].angle_with(Vector[-1, 0]))
+    assert_in_epsilon(Math::PI/2, Vector[1, 0].angle_with(Vector[0, -1]))
+    assert_in_epsilon(Math::PI/4, Vector[2, 2].angle_with(Vector[0, 1]))
+    assert_in_delta(0.0, Vector[1, 1].angle_with(Vector[1, 1]), 0.00001)
+
+    assert_raise(Vector::ZeroVectorError) { Vector[1, 1].angle_with(Vector[0, 0]) }
+    assert_raise(Vector::ZeroVectorError) { Vector[0, 0].angle_with(Vector[1, 1]) }
+    assert_raise(Matrix::ErrDimensionMismatch) { Vector[1, 2, 3].angle_with(Vector[0, 1]) }
+  end
 end

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