* lib/matrix.rb: Add Vector.zero and Vector#zero?

  Patch by Chia-sheng Chen [#13208]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57976 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 20 insertions, 0 deletions

diff --git a/lib/matrix.rb b/lib/matrix.rb
index eaa4bfc6e1..77c35b3475 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -1685,6 +1685,7 @@ end
 # * Vector.[](*array)
 # * Vector.elements(array, copy = true)
 # * Vector.basis(size: n, index: k)
+# * Vector.zero(n)
 #
 # To access elements:
 # * #[](i)
@@ -1697,6 +1698,7 @@ end
 # * #angle_with(v)
 # * Vector.independent?(*vs)
 # * #independent?(*vs)
+# * #zero?
 #
 # Vector arithmetic:
 # * #*(x) "is matrix or number"
@@ -1769,6 +1771,17 @@ class Vector
   end
 
   #
+  # Return a zero vector.
+  #
+  #    Vector.zero(3) => Vector[0, 0, 0]
+  #
+  def Vector.zero(size)
+    raise ArgumentError, "invalid size (#{size} for 0..)" if size < 0
+    array = Array.new(size, 0)
+    new convert_to_array(array, false)
+  end
+
+  #
   # Vector.new is private; use Vector[] or Vector.elements to create.
   #
   def initialize(array)
@@ -1882,6 +1895,13 @@ class Vector
     self.class.independent?(self, *vs)
   end
 
+  #
+  # Returns +true+ iff all elements are zero.
+  #
+  def zero?
+    all?(&:zero?)
+  end
+
   #--
   # COMPARING -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
   #++