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Diffstat (limited to 'spec/rubyspec/library/matrix/shared/determinant.rb')
-rw-r--r-- | spec/rubyspec/library/matrix/shared/determinant.rb | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/spec/rubyspec/library/matrix/shared/determinant.rb b/spec/rubyspec/library/matrix/shared/determinant.rb new file mode 100644 index 0000000000..47a58c62a6 --- /dev/null +++ b/spec/rubyspec/library/matrix/shared/determinant.rb @@ -0,0 +1,38 @@ +require 'matrix' + +describe :determinant, shared: true do + it "returns the determinant of a square Matrix" do + m = Matrix[ [7,6], [3,9] ] + m.send(@method).should == 45 + + m = Matrix[ [9, 8], [6,5] ] + m.send(@method).should == -3 + + m = Matrix[ [9,8,3], [4,20,5], [1,1,1] ] + m.send(@method).should == 95 + end + + it "returns the determinant of a single-element Matrix" do + m = Matrix[ [2] ] + m.send(@method).should == 2 + end + + it "returns 1 for an empty Matrix" do + m = Matrix[ ] + m.send(@method).should == 1 + end + + it "returns the determinant even for Matrices containing 0 as first entry" do + Matrix[[0,1],[1,0]].send(@method).should == -1 + end + + it "raises an error for rectangular matrices" do + lambda { + Matrix[[1], [2], [3]].send(@method) + }.should raise_error(Matrix::ErrDimensionMismatch) + + lambda { + Matrix.empty(3,0).send(@method) + }.should raise_error(Matrix::ErrDimensionMismatch) + end +end |