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_from_profile(), 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_from_profile(), 0)
        self.assertTrue(
            surf.rms_height_from_profile() < UniformLineScan(arr, arr.shape).rms_height_from_profile())

        surf2 = UniformLineScan(arr, (1,)).detrend(detrend_mode='height')
        self.assertEqual(surf.dim, 1)
        self.assertTrue(surf2.is_uniform)
        self.assertAlmostEqual(surf2.rms_slope_from_profile(), 0)
        self.assertTrue(
            surf2.rms_height_from_profile() < UniformLineScan(arr, arr.shape).rms_height_from_profile())

        self.assertAlmostEqual(surf.rms_height_from_profile(), surf2.rms_height_from_profile())

        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_from_profile(),
                                detrended.rms_slope_from_profile(),
                                msg=mode)
         else:
             self.assertGreater(t.rms_height_from_profile(),
                                detrended.rms_height_from_profile(),
                                msg=mode)