lib/matrix: Add hadamard_product/entrywise_product.

Based on a patch by Charley Hutchison. [GH-674]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60860 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/matrix.rb b/lib/matrix.rb
index 2f2d0f371a..d242665ef9 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -980,6 +980,17 @@ class Matrix
   end
 
   #
+  # Hadamard product
+  #    Matrix[[1,2], [3,4]].hadamard_product(Matrix[[1,2], [3,2]])
+  #      => 1  4
+  #         9  8
+  #
+  def hadamard_product(m)
+    combine(m){|a, b| a * b}
+  end
+  alias_method :entrywise_product, :hadamard_product
+
+  #
   # Returns the inverse of the matrix.
   #   Matrix[[-1, -1], [0, -1]].inverse
   #     => -1  1