* lib/matrix.rb: Add Matrix#adjucate

  patch by gogo tanaka [#10056]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48182 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 15 insertions, 0 deletions

diff --git a/lib/matrix.rb b/lib/matrix.rb
index cdaa55f157..f7acd9f1fc 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -62,6 +62,7 @@ end
 # * #minor(*param)
 # * #first_minor(row, column)
 # * #cofactor(row, column)
+# * #adjugate
 # * #laplace_expansion(row_or_column: num)
 # * #cofactor_expansion(row_or_column: num)
 #
@@ -690,6 +691,20 @@ class Matrix
   end
 
   #
+  # Returns the adjugate of the matrix.
+  #
+  #   Matrix[ [7,6],[3,9] ].adjugate
+  #     => 9 -6
+  #        -3 7
+  #
+  def adjugate
+    Matrix.Raise ErrDimensionMismatch unless square?
+    Matrix.build(row_count, column_count) do |row, column|
+      cofactor(column, row)
+    end
+  end
+
+  #
   # Returns the Laplace expansion along given row or column.
   #
   #    Matrix[[7,6], [3,9]].laplace_expansion(column: 1)