diff options
| -rw-r--r-- | NEWS | 4 | ||||
| -rw-r--r-- | lib/matrix.rb | 9 | ||||
| -rw-r--r-- | spec/ruby/library/matrix/reflexive_spec.rb | 31 |
3 files changed, 43 insertions, 1 deletions
@@ -264,10 +264,12 @@ sufficient information, see the ChangeLog file or Redmine * `Matrix` - * New method: + * New methods: * `Matrix#antisymmetric?` + * `Matrix#reflexive?` + * `Net` * New options: diff --git a/lib/matrix.rb b/lib/matrix.rb index 7639b1de6d..62852bdad0 100644 --- a/lib/matrix.rb +++ b/lib/matrix.rb @@ -814,6 +814,15 @@ class Matrix 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. # diff --git a/spec/ruby/library/matrix/reflexive_spec.rb b/spec/ruby/library/matrix/reflexive_spec.rb new file mode 100644 index 0000000000..380fbb7ed6 --- /dev/null +++ b/spec/ruby/library/matrix/reflexive_spec.rb @@ -0,0 +1,31 @@ +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 |