def test_nonuniform3(self):
x = np.array((1, 2, 3, 4))
y = -2 * x
surf = NonuniformLineScan(x, y)
self.assertFalse(surf.is_uniform)
self.assertEqual(surf.dim, 1)
der = surf.derivative(n=1)
assert_array_equal(der, [-2, -2, -2])
der = surf.derivative(n=2)
assert_array_equal(der, [0, 0])
#
# Similar with detrend which substracts mean value
#
surf2 = surf.detrend(detrend_mode='center')
self.assertFalse(surf2.is_uniform)
self.assertEqual(surf.dim, 1)
der = surf2.derivative(n=1)
assert_array_equal(der, [-2, -2, -2])
#
# Similar with detrend which eliminates slope
#
surf3 = surf.detrend(detrend_mode='height')
self.assertFalse(surf3.is_uniform)
self.assertEqual(surf.dim, 1)
der = surf3.derivative(n=1)
np.testing.assert_allclose(der, [0, 0, 0], atol=1e-14)
np.testing.assert_allclose(surf3.heights(),
np.zeros(y.shape),
atol=1e-14)
p = surf3.positions_and_heights()
assert_array_equal(p[0], x)
np.testing.assert_allclose(p[1], np.zeros(y.shape), atol=1e-14)
def test_nonuniform2(self):
x = np.array((1, 2, 3))
y = 2 * x
surf = NonuniformLineScan(x, y)
self.assertFalse(surf.is_uniform)
self.assertEqual(surf.dim, 1)
der = surf.derivative(n=1)
assert_array_equal(der, [2, 2])
der = surf.derivative(n=2)
assert_array_equal(der, [0])
surf = surf.detrend(detrend_mode='height')
self.assertFalse(surf.is_uniform)
self.assertEqual(surf.dim, 1)
der = surf.derivative(n=1)
assert_array_equal(der, [0, 0])
assert_array_equal(surf.heights(), np.zeros(y.shape))
p = surf.positions_and_heights()
assert_array_equal(p[0], x)
assert_array_equal(p[1], np.zeros(y.shape))