def test_smooth_flat_1d(self):
arr = self._flat_arr
a = 1.2
d = .2
arr = np.arange(5) * a + d
surf = UniformLineScan(arr, (1, )).detrend(detrend_mode='center')
self.assertTrue(surf.is_uniform)
self.assertAlmostEqual(surf.mean(), 0)
surf = UniformLineScan(arr, (1.5, )).detrend(detrend_mode='slope')
self.assertEqual(surf.dim, 1)
self.assertTrue(surf.is_uniform)
self.assertAlmostEqual(surf.mean(), 0)
self.assertAlmostEqual(surf.rms_slope(), 0)
surf = UniformLineScan(arr, arr.shape).detrend(detrend_mode='height')
self.assertEqual(surf.dim, 1)
self.assertTrue(surf.is_uniform)
self.assertAlmostEqual(surf.mean(), 0)
self.assertAlmostEqual(surf.rms_slope(), 0)
self.assertTrue(
surf.rms_height() < UniformLineScan(arr, arr.shape).rms_height())
surf2 = UniformLineScan(arr, (1, )).detrend(detrend_mode='height')
self.assertEqual(surf.dim, 1)
self.assertTrue(surf2.is_uniform)
self.assertAlmostEqual(surf2.rms_slope(), 0)
self.assertTrue(
surf2.rms_height() < UniformLineScan(arr, arr.shape).rms_height())
self.assertAlmostEqual(surf.rms_height(), surf2.rms_height())
x, z = surf2.positions_and_heights()
self.assertAlmostEqual(np.mean(np.diff(x)),
surf2.physical_sizes[0] / surf2.nb_grid_pts[0])
def test_detrend_reduces(self):
""" tests if detrending really reduces the heights (or slope) as claimed
"""
n = 10
dx = 0.5
h = [
0.82355941, -1.32205074, 0.77084813, 0.49928252, 0.57872149,
2.80200331, 0.09551251, -1.11616977, 2.07630937, -0.65408072
]
t = UniformLineScan(h, dx * n)
for mode in ['height', 'curvature', 'slope']:
detrended = t.detrend(detrend_mode=mode)
self.assertAlmostEqual(detrended.mean(), 0)
if mode == 'slope':
self.assertGreater(t.rms_slope(),
detrended.rms_slope(),
msg=mode)
else:
self.assertGreater(t.rms_height(),
detrended.rms_height(),
msg=mode)