110 lines
4.7 KiB
Python
110 lines
4.7 KiB
Python
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#!/usr/bin/env python
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from __future__ import division, print_function, absolute_import
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import numpy as np
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from numpy.testing import assert_raises, assert_equal, assert_allclose
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import pywt
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def test_available_modes():
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modes = ['zero', 'constant', 'symmetric', 'periodic', 'smooth',
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'periodization', 'reflect', 'antisymmetric', 'antireflect']
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assert_equal(pywt.Modes.modes, modes)
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assert_equal(pywt.Modes.from_object('constant'), 2)
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def test_invalid_modes():
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x = np.arange(4)
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assert_raises(ValueError, pywt.dwt, x, 'db2', 'unknown')
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assert_raises(ValueError, pywt.dwt, x, 'db2', -1)
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assert_raises(ValueError, pywt.dwt, x, 'db2', 9)
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assert_raises(TypeError, pywt.dwt, x, 'db2', None)
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assert_raises(ValueError, pywt.Modes.from_object, 'unknown')
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assert_raises(ValueError, pywt.Modes.from_object, -1)
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assert_raises(ValueError, pywt.Modes.from_object, 9)
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assert_raises(TypeError, pywt.Modes.from_object, None)
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def test_dwt_idwt_allmodes():
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# Test that :func:`dwt` and :func:`idwt` can be performed using every mode
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x = [1, 2, 1, 5, -1, 8, 4, 6]
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dwt_results = {
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'zero': ([-0.03467518, 1.73309178, 3.40612438, 6.32928585, 6.95094948],
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[-0.12940952, -2.15599552, -5.95034847, -1.21545369,
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-1.8625013]),
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'constant': ([1.28480404, 1.73309178, 3.40612438, 6.32928585,
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7.51935555],
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[-0.48296291, -2.15599552, -5.95034847, -1.21545369,
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0.25881905]),
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'symmetric': ([1.76776695, 1.73309178, 3.40612438, 6.32928585,
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7.77817459],
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[-0.61237244, -2.15599552, -5.95034847, -1.21545369,
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1.22474487]),
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'reflect': ([2.12132034, 1.73309178, 3.40612438, 6.32928585,
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6.81224877],
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[-0.70710678, -2.15599552, -5.95034847, -1.21545369,
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-2.38013939]),
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'periodic': ([6.9162743, 1.73309178, 3.40612438, 6.32928585,
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6.9162743],
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[-1.99191082, -2.15599552, -5.95034847, -1.21545369,
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-1.99191082]),
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'smooth': ([-0.51763809, 1.73309178, 3.40612438, 6.32928585,
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7.45000519],
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[0, -2.15599552, -5.95034847, -1.21545369, 0]),
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'periodization': ([4.053172, 3.05257099, 2.85381112, 8.42522221],
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[0.18946869, 4.18258152, 4.33737503, 2.60428326]),
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'antisymmetric': ([-1.83711731, 1.73309178, 3.40612438, 6.32928585,
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6.12372436],
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[0.353553391, -2.15599552, -5.95034847, -1.21545369,
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-4.94974747]),
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'antireflect': ([0.44828774, 1.73309178, 3.40612438, 6.32928585,
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8.22646233],
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[-0.25881905, -2.15599552, -5.95034847, -1.21545369,
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2.89777748])
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}
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for mode in pywt.Modes.modes:
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cA, cD = pywt.dwt(x, 'db2', mode)
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assert_allclose(cA, dwt_results[mode][0], rtol=1e-7, atol=1e-8)
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assert_allclose(cD, dwt_results[mode][1], rtol=1e-7, atol=1e-8)
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assert_allclose(pywt.idwt(cA, cD, 'db2', mode), x, rtol=1e-10)
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def test_dwt_short_input_allmodes():
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# some test cases where the input is shorter than the DWT filter
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x = [1, 3, 2]
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wavelet = 'db2'
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# manually pad each end by the filter size (4 for 'db2' used here)
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padded_x = {'zero': [0, 0, 0, 0, 1, 3, 2, 0, 0, 0, 0],
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'constant': [1, 1, 1, 1, 1, 3, 2, 2, 2, 2, 2],
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'symmetric': [2, 2, 3, 1, 1, 3, 2, 2, 3, 1, 1],
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'reflect': [1, 3, 2, 3, 1, 3, 2, 3, 1, 3, 2],
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'periodic': [2, 1, 3, 2, 1, 3, 2, 1, 3, 2, 1],
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'smooth': [-7, -5, -3, -1, 1, 3, 2, 1, 0, -1, -2],
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'antisymmetric': [2, -2, -3, -1, 1, 3, 2, -2, -3, -1, 1],
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'antireflect': [1, -1, 0, -1, 1, 3, 2, 1, 3, 5, 4],
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}
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for mode, xpad in padded_x.items():
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# DWT of the manually padded array. will discard edges later so
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# symmetric mode used here doesn't matter.
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cApad, cDpad = pywt.dwt(xpad, wavelet, mode='symmetric')
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# central region of the padded output (unaffected by mode )
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expected_result = (cApad[2:-2], cDpad[2:-2])
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cA, cD = pywt.dwt(x, wavelet, mode)
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assert_allclose(cA, expected_result[0], rtol=1e-7, atol=1e-8)
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assert_allclose(cD, expected_result[1], rtol=1e-7, atol=1e-8)
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def test_default_mode():
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# The default mode should be 'symmetric'
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x = [1, 2, 1, 5, -1, 8, 4, 6]
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cA, cD = pywt.dwt(x, 'db2')
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cA2, cD2 = pywt.dwt(x, 'db2', mode='symmetric')
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assert_allclose(cA, cA2)
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assert_allclose(cD, cD2)
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assert_allclose(pywt.idwt(cA, cD, 'db2'), x)
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