def test_cubic(self):
signal = np.array([-1.0, -0.125, 0.0, 0.125, 1.0])
expected_coeffs = np.array([0.0, 0.0, 0.0, 1.0])
expected_diff = 0.0
expected_approx = np.power(np.linspace(-1, 1, 5), 3)
actual_coeffs, actual_approx, actual_diff = utils._fit_poly(3, signal)
self.assertTrue(array_equal(expected_coeffs, actual_coeffs))
self.assertTrue(array_equal(expected_approx, actual_approx))
self.assertTrue(array_equal(expected_diff, actual_diff))
def test_line(self):
signal = np.array([-1.0, 1.0])
expected_coeffs = np.array([0.0, 1.0])
expected_diff = 0.0
expected_approx = signal
actual_coeffs, actual_approx, actual_diff = utils._fit_poly(1, signal)
self.assertTrue(array_equal(expected_coeffs, actual_coeffs))
self.assertTrue(array_equal(expected_approx, actual_approx))
self.assertTrue(array_equal(expected_diff, actual_diff))
def test_grid_not_centered(self):
grid = np.array([0, 1, 2, 3, 4])
signal = np.array([4, 1, 0, 1, 4])
expected_coeffs = np.array([0.0, 0.0, 1.0])
expected_diff = 0.0
expected_approx = np.power(grid - 2.0, 2)
actual_coeffs, actual_approx, actual_diff = utils._fit_poly(
2, signal, grid=grid
)
self.assertTrue(array_equal(expected_coeffs, actual_coeffs))
self.assertTrue(array_equal(expected_approx, actual_approx))
self.assertTrue(array_equal(expected_diff, actual_diff))
def test_too_short(self):
with self.assertRaises(ValueError):
utils._fit_poly(5, np.array([0.0, 1.0]))