spec/ruby/library/matrix/lup_decomposition/p_spec.rb


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require_relative '../../../spec_helper'

ruby_version_is ""..."3.1" do
  require 'matrix'

  describe "Matrix::LUPDecomposition#p" do
    before :each do
      @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
      @lu = Matrix::LUPDecomposition.new(@a)
      @p = @lu.p
    end

    it "returns the third element of to_a" do
      @p.should == @lu.to_a[2]
    end

    it "returns a permutation matrix" do
      @p.permutation?.should be_true
    end
  end
end