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#!/usr/bin/env python
import os
import pickle
import numpy as np
from numpy.testing import (assert_allclose, assert_, assert_raises,
assert_equal)
import pywt
def test_wavelet_packet_structure():
x = [1, 2, 3, 4, 5, 6, 7, 8]
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric')
assert_(wp.data == [1, 2, 3, 4, 5, 6, 7, 8])
assert_(wp.path == '')
assert_(wp.level == 0)
assert_(wp['ad'].maxlevel == 3)
def test_traversing_wp_tree():
x = [1, 2, 3, 4, 5, 6, 7, 8]
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric')
assert_(wp.maxlevel == 3)
# First level
assert_allclose(wp['a'].data, np.array([2.12132034356, 4.949747468306,
7.778174593052, 10.606601717798]),
rtol=1e-12)
# Second level
assert_allclose(wp['aa'].data, np.array([5., 13.]), rtol=1e-12)
# Third level
assert_allclose(wp['aaa'].data, np.array([12.727922061358]), rtol=1e-12)
def test_acess_path():
x = [1, 2, 3, 4, 5, 6, 7, 8]
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric')
assert_(wp['a'].path == 'a')
assert_(wp['aa'].path == 'aa')
assert_(wp['aaa'].path == 'aaa')
# Maximum level reached:
assert_raises(IndexError, lambda: wp['aaaa'].path)
# Wrong path
assert_raises(ValueError, lambda: wp['ac'].path)
def test_access_node_attributes():
x = [1, 2, 3, 4, 5, 6, 7, 8]
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric')
assert_allclose(wp['ad'].data, np.array([-2., -2.]), rtol=1e-12)
assert_(wp['ad'].path == 'ad')
assert_(wp['ad'].node_name == 'd')
assert_(wp['ad'].parent.path == 'a')
assert_(wp['ad'].level == 2)
assert_(wp['ad'].maxlevel == 3)
assert_(wp['ad'].mode == 'symmetric')
# tuple-based access is also supported
node = wp[('a', 'd')]
# can access a node's path as either a single string or in tuple form
assert_(node.path == 'ad')
assert_(node.path_tuple == ('a', 'd'))
def test_collecting_nodes():
x = [1, 2, 3, 4, 5, 6, 7, 8]
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric')
# All nodes in natural order
assert_([node.path for node in wp.get_level(3, 'natural')] ==
['aaa', 'aad', 'ada', 'add', 'daa', 'dad', 'dda', 'ddd'])
# and in frequency order.
assert_([node.path for node in wp.get_level(3, 'freq')] ==
['aaa', 'aad', 'add', 'ada', 'dda', 'ddd', 'dad', 'daa'])
assert_raises(ValueError, wp.get_level, 3, 'invalid_order')
def test_reconstructing_data():
x = [1, 2, 3, 4, 5, 6, 7, 8]
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric')
# Create another Wavelet Packet and feed it with some data.
new_wp = pywt.WaveletPacket(data=None, wavelet='db1', mode='symmetric')
new_wp['aa'] = wp['aa'].data
new_wp['ad'] = [-2., -2.]
# For convenience, :attr:`Node.data` gets automatically extracted
# from the :class:`Node` object:
new_wp['d'] = wp['d']
# Reconstruct data from aa, ad, and d packets.
assert_allclose(new_wp.reconstruct(update=False), x, rtol=1e-12)
# The node's :attr:`~Node.data` will not be updated
assert_(new_wp.data is None)
# When `update` is True:
assert_allclose(new_wp.reconstruct(update=True), x, rtol=1e-12)
assert_allclose(new_wp.data, np.arange(1, 9), rtol=1e-12)
assert_([n.path for n in new_wp.get_leaf_nodes(False)] ==
['aa', 'ad', 'd'])
assert_([n.path for n in new_wp.get_leaf_nodes(True)] ==
['aaa', 'aad', 'ada', 'add', 'daa', 'dad', 'dda', 'ddd'])
def test_removing_nodes():
x = [1, 2, 3, 4, 5, 6, 7, 8]
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric')
wp.get_level(2)
dataleafs = [n.data for n in wp.get_leaf_nodes(False)]
expected = np.array([[5., 13.], [-2, -2], [-1, -1], [0, 0]])
for i in range(4):
assert_allclose(dataleafs[i], expected[i, :], atol=1e-12)
node = wp['ad']
del(wp['ad'])
dataleafs = [n.data for n in wp.get_leaf_nodes(False)]
expected = np.array([[5., 13.], [-1, -1], [0, 0]])
for i in range(3):
assert_allclose(dataleafs[i], expected[i, :], atol=1e-12)
wp.reconstruct()
# The reconstruction is:
assert_allclose(wp.reconstruct(),
np.array([2., 3., 2., 3., 6., 7., 6., 7.]), rtol=1e-12)
# Restore the data
wp['ad'].data = node.data
dataleafs = [n.data for n in wp.get_leaf_nodes(False)]
expected = np.array([[5., 13.], [-2, -2], [-1, -1], [0, 0]])
for i in range(4):
assert_allclose(dataleafs[i], expected[i, :], atol=1e-12)
assert_allclose(wp.reconstruct(), np.arange(1, 9), rtol=1e-12)
def test_wavelet_packet_dtypes():
rstate = np.random.RandomState(0)
N = 32
for dtype in [np.float32, np.float64, np.complex64, np.complex128]:
x = rstate.randn(N).astype(dtype)
if np.iscomplexobj(x):
x = x + 1j*np.random.randn(N).astype(x.real.dtype)
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric')
# no unnecessary copy made
assert_(wp.data is x)
# assigning to a node should not change supported dtypes
wp['d'] = wp['d'].data
assert_equal(wp['d'].data.dtype, x.dtype)
# full decomposition
wp.get_level(wp.maxlevel)
# reconstruction from coefficients should preserve dtype
r = wp.reconstruct(False)
assert_equal(r.dtype, x.dtype)
assert_allclose(r, x, atol=1e-5, rtol=1e-5)
# first element of the tuple is the input dtype
# second element of the tuple is the transform dtype
dtype_pairs = [(np.uint8, np.float64),
(np.intp, np.float64), ]
if hasattr(np, "complex256"):
dtype_pairs += [(np.complex256, np.complex128), ]
if hasattr(np, "half"):
dtype_pairs += [(np.half, np.float32), ]
for (dtype, transform_dtype) in dtype_pairs:
x = np.arange(N, dtype=dtype)
wp = pywt.WaveletPacket(x, wavelet='db1', mode='symmetric')
# no unnecessary copy made of top-level data
assert_(wp.data is x)
# full decomposition
wp.get_level(wp.maxlevel)
# reconstructed data will have modified dtype
r = wp.reconstruct(False)
assert_equal(r.dtype, transform_dtype)
assert_allclose(r, x.astype(transform_dtype), atol=1e-5, rtol=1e-5)
def test_db3_roundtrip():
original = np.arange(512)
wp = pywt.WaveletPacket(data=original, wavelet='db3', mode='smooth',
maxlevel=3)
r = wp.reconstruct()
assert_allclose(original, r, atol=1e-12, rtol=1e-12)
def test_wavelet_packet_axis():
rstate = np.random.RandomState(0)
shape = (32, 16)
x = rstate.standard_normal(shape)
for axis in [0, 1, -1]:
wp = pywt.WaveletPacket(data=x, wavelet='db1', mode='symmetric',
axis=axis)
# partial decomposition
nodes = wp.get_level(2)
# size along the transformed axis has changed
for ax2 in range(x.ndim):
if ax2 == (axis % x.ndim):
nodes[0].data.shape[ax2] < x.shape[ax2]
else:
nodes[0].data.shape[ax2] == x.shape[ax2]
# recontsruction from coefficients should preserve dtype
r = wp.reconstruct(False)
assert_equal(r.dtype, x.dtype)
assert_allclose(r, x, atol=1e-12, rtol=1e-12)
# ValueError if axis is out of range
assert_raises(ValueError, pywt.WaveletPacket, data=x, wavelet='db1',
axis=x.ndim)
def test_wavelet_packet_pickle(tmpdir):
packet = pywt.WaveletPacket(np.arange(16), 'sym4')
filename = os.path.join(tmpdir, 'wp.pickle')
with open(filename, 'wb') as f:
pickle.dump(packet, f)
with open(filename, 'rb') as f:
packet2 = pickle.load(f)
assert isinstance(packet2, pywt.WaveletPacket)
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