def test_basic(self):
"""Check a few basic examples of the tie correction factor."""
# One tie of two elements
ranks = np.array([1.0, 2.5, 2.5])
c = tiecorrect(ranks)
T = 2.0
N = ranks.size
expected = 1.0 - (T ** 3 - T) / (N ** 3 - N)
assert_equal(c, expected)
# One tie of two elements (same as above, but tie is not at the end)
ranks = np.array([1.5, 1.5, 3.0])
c = tiecorrect(ranks)
T = 2.0
N = ranks.size
expected = 1.0 - (T ** 3 - T) / (N ** 3 - N)
assert_equal(c, expected)
# One tie of three elements
ranks = np.array([1.0, 3.0, 3.0, 3.0])
c = tiecorrect(ranks)
T = 3.0
N = ranks.size
expected = 1.0 - (T ** 3 - T) / (N ** 3 - N)
assert_equal(c, expected)
# Two ties, lengths 2 and 3.
ranks = np.array([1.5, 1.5, 4.0, 4.0, 4.0])
c = tiecorrect(ranks)
T1 = 2.0
T2 = 3.0
N = ranks.size
expected = 1.0 - ((T1 ** 3 - T1) + (T2 ** 3 - T2)) / (N ** 3 - N)
assert_equal(c, expected)
def test_basic(self):
"""Check a few basic examples of the tie correction factor."""
# One tie of two elements
ranks = np.array([1.0, 2.5, 2.5])
c = tiecorrect(ranks)
T = 2.0
N = ranks.size
expected = 1.0 - (T**3 - T) / (N**3 - N)
assert_equal(c, expected)
# One tie of two elements (same as above, but tie is not at the end)
ranks = np.array([1.5, 1.5, 3.0])
c = tiecorrect(ranks)
T = 2.0
N = ranks.size
expected = 1.0 - (T**3 - T) / (N**3 - N)
assert_equal(c, expected)
# One tie of three elements
ranks = np.array([1.0, 3.0, 3.0, 3.0])
c = tiecorrect(ranks)
T = 3.0
N = ranks.size
expected = 1.0 - (T**3 - T) / (N**3 - N)
assert_equal(c, expected)
# Two ties, lengths 2 and 3.
ranks = np.array([1.5, 1.5, 4.0, 4.0, 4.0])
c = tiecorrect(ranks)
T1 = 2.0
T2 = 3.0
N = ranks.size
expected = 1.0 - ((T1**3 - T1) + (T2**3 - T2)) / (N**3 - N)
assert_equal(c, expected)
def test_no_correction(self):
"""Arrays with no ties require no correction."""
ranks = np.arange(2.0)
c = tiecorrect(ranks)
assert_equal(c, 1.0)
ranks = np.arange(3.0)
c = tiecorrect(ranks)
assert_equal(c, 1.0)
def test_no_correction(self):
"""Arrays with no ties require no correction."""
ranks = np.arange(2.0)
c = tiecorrect(ranks)
assert_equal(c, 1.0)
ranks = np.arange(3.0)
c = tiecorrect(ranks)
assert_equal(c, 1.0)
def test_empty(self):
"""An empty array requires no correction, should return 1.0."""
ranks = np.array([], dtype=np.float64)
c = tiecorrect(ranks)
assert_equal(c, 1.0)
def test_one(self):
"""A single element requires no correction, should return 1.0."""
ranks = np.array([1.0], dtype=np.float64)
c = tiecorrect(ranks)
assert_equal(c, 1.0)
def test_empty(self):
"""An empty array requires no correction, should return 1.0."""
ranks = np.array([], dtype=np.float64)
c = tiecorrect(ranks)
assert_equal(c, 1.0)
def test_one(self):
"""A single element requires no correction, should return 1.0."""
ranks = np.array([1.0], dtype=np.float64)
c = tiecorrect(ranks)
assert_equal(c, 1.0)