Revert "Matrix: Add #reflexive? method. [Fix GH-1730]"

This reverts commit 19fe6552c4.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65500 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

NEWS

@@ -313,8 +313,6 @@ sufficient information, see the ChangeLog file or Redmine
 
     * Matrix#antisymmetric?
 
-    * Matrix#reflexive?
-
 [Net]
 
   [New options]

lib/matrix.rb

@@ -813,15 +813,6 @@ class Matrix
     true
   end
 
-  #
-  # Returns +true+ if this is a reflexive matrix.
-  # Raises an error if matrix is not square.
-  #
-  def reflexive?
-    Matrix.Raise ErrDimensionMismatch unless square?
-    each(:diagonal).all? { |e| e == 1 }
-  end
-
   #
   # Returns +true+ if this is a unitary matrix
   # Raises an error if matrix is not square.

spec/ruby/library/matrix/reflexive_spec.rb

@@ -1,31 +0,0 @@
-require File.expand_path('../../../spec_helper', __FILE__)
-require 'matrix'
-
-ruby_version_is '2.6' do
-  describe "Matrix.reflexive?" do
-    it "returns true for a reflexive Matrix" do
-      Matrix[[1, 2, 3], [4, 1, 3], [5, 3, 1]].reflexive?.should be_true
-    end
-
-    it "returns true for a 0x0 empty matrix" do
-      Matrix.empty.reflexive?.should be_true
-    end
-
-    it "returns false for a non-reflexive Matrix" do
-      Matrix[[1, 1],[2, 2]].reflexive?.should be_false
-    end
-
-    it "raises an error for non-square matrices" do
-      [
-        Matrix[[0], [0]],
-        Matrix[[0, 0]],
-        Matrix.empty(0, 2),
-        Matrix.empty(2, 0),
-      ].each do |rectangular_matrix|
-        lambda {
-          rectangular_matrix.reflexive?
-        }.should raise_error(Matrix::ErrDimensionMismatch)
-      end
-    end
-  end
-end