svm_toolkit/test/problem_test.rb

require 'svm_toolkit'
require 'minitest/autorun'

include SvmToolkit

class TestProblem < MiniTest::Test
  def test_raise_exception
    assert_raises(ArgumentError) { Problem.from_array([], []) }
    assert_raises(ArgumentError) { Problem.from_array([], [1,2,3]) }
    assert_raises(ArgumentError) { Problem.from_array([[1],[2],[3]], [1,2]) }
    assert_raises(ArgumentError) { Problem.from_array([[1],[2,3],[4]], [1,2,3])}
  end

  def test_create_problem_from_array
    problem = Problem.from_array([[1,2],[2,3],[3,4]], [1,2,3])
    assert_equal(3, problem.size)
    assert_equal(2, problem.x[1][0].value)
    assert_equal(1, problem.y[0])
  end

  def test_rescale_problem
    problem = Problem.from_array(
      [[1,2,3], [1.5, 4, 3.1], [2.0, 6, 3.2]],
      [1, 0, 1]
    )
    assert_equal(3, problem.size)
    assert_equal(1, problem.x[0][0].value)
    assert_equal(2.0, problem.x[2][0].value)

    problem.rescale(-1.0, 1.0)
    assert_equal(3, problem.size)
    assert_equal(-1, problem.x[0][0].value)
    assert_equal(0, problem.x[1][0].value)
    assert_equal(1, problem.x[2][0].value)
    assert_equal(-1, problem.x[0][1].value)
    assert_equal(0, problem.x[1][1].value)
    assert_equal(1, problem.x[2][1].value)
    assert_equal(-1, problem.x[0][1].value)
    assert_equal(0, problem.x[1][1].value)
    assert_equal(1, problem.x[2][1].value)

    problem.rescale(0.0, 1.0)
    assert_equal(3, problem.size)
    assert_equal(0, problem.x[0][0].value)
    assert_equal(0.5, problem.x[1][0].value)
    assert_equal(1.0, problem.x[2][0].value)
    assert_equal(0, problem.x[0][1].value)
    assert_equal(0.5, problem.x[1][1].value)
    assert_equal(1.0, problem.x[2][1].value)
    assert_equal(0, problem.x[0][1].value)
    assert_equal(0.5, problem.x[1][1].value)
    assert_equal(1.0, problem.x[2][1].value)
  end

  def test_merge_problems
    problem1 = Problem.from_array(
      [[1,2,3], [1.5, 4, 3.1], [2.0, 6, 3.2]],
      [1, 0, 1]
    )
    problem2 = Problem.from_array(
      [[1,2,3,4]], [1]
    )
    # problems with differing numbers of features cannot be merged
    assert_raises(ArgumentError) { problem1.merge(problem2) }
    problem3 = Problem.from_array(
      [[1,2,3], [1.5, 4, 3.1], [2.0, 6, 3.2]],
      [1, 0, 1]
    )
    # confirm merging of two problems
    problem1.merge problem3
    problem4 = problem1.merge problem3
    assert_equal(6, problem4.size)
    [[1,2,3], [1.5, 4, 3.1], [2.0, 6, 3.2], 
     [1,2,3], [1.5, 4, 3.1], [2.0, 6, 3.2]
    ].each_with_index do |instance, i|
      instance.each_with_index do |v, j|
        assert_equal(v, problem4.x[i][j].value)
      end
    end
    [1,0,1,1,0,1].each_with_index do |v, i|
      assert_equal(v, problem4.y[i])
    end
  end
end