def __init__(self, n_basis, family, n_aux=15):
self.n_basis = n_basis
## Generate wavelet on fine grid
wav = pywt.DiscreteContinuousWavelet(family)
_, self.wavelet, self.x_grid = wav.wavefun(n_aux)
self.N = max(self.x_grid)
def test_swt2_iswt2_integration():
# This function performs a round-trip swt2/iswt2 transform test on
# all available types of wavelets in PyWavelets - except the
# 'dmey' wavelet. The latter has been excluded because it does not
# produce very precise results. This is likely due to the fact
# that the 'dmey' wavelet is a discrete approximation of a
# continuous wavelet. All wavelets are tested up to 3 levels. The
# test validates neither swt2 or iswt2 as such, but it does ensure
# that they are each other's inverse.
max_level = 3
wavelets = pywt.wavelist()
if 'dmey' in wavelets:
# The 'dmey' wavelet seems to be a bit special - disregard it for now
wavelets.remove('dmey')
for current_wavelet_str in wavelets:
current_wavelet = pywt.DiscreteContinuousWavelet(current_wavelet_str)
if isinstance(current_wavelet, pywt.Wavelet):
input_length_power = int(
np.ceil(
np.log2(
max(current_wavelet.dec_len,
current_wavelet.rec_len))))
input_length = 2**(input_length_power + max_level - 1)
X = np.arange(input_length**2).reshape(input_length, input_length)
with warnings.catch_warnings():
warnings.simplefilter('ignore', FutureWarning)
coeffs = pywt.swt2(X, current_wavelet, max_level)
Y = pywt.iswt2(coeffs, current_wavelet)
assert_allclose(Y, X, rtol=1e-5, atol=1e-5)
def test_error_on_continuous_wavelet():
# A ValueError is raised if a Continuous wavelet is selected
data = np.ones((32, ))
for cwave in ['morl', pywt.DiscreteContinuousWavelet('morl')]:
assert_raises(ValueError, pywt.dwt, data, cwave)
cA, cD = pywt.dwt(data, 'db1')
assert_raises(ValueError, pywt.idwt, cA, cD, cwave)
def test_error_on_continuous_wavelet():
# A ValueError is raised if a Continuous wavelet is selected
data = np.ones((16, 16))
for dec_fun, rec_fun in zip([pywt.wavedec, pywt.wavedec2, pywt.wavedecn],
[pywt.waverec, pywt.waverec2, pywt.waverecn]):
for cwave in ['morl', pywt.DiscreteContinuousWavelet('morl')]:
assert_raises(ValueError, dec_fun, data, wavelet=cwave)
c = dec_fun(data, 'db1')
assert_raises(ValueError, rec_fun, c, wavelet=cwave)
def test_error_on_continuous_wavelet():
# A ValueError is raised if a Continuous wavelet is selected
data = np.ones((16, 16))
for dec_func, rec_func in zip([pywt.swt, pywt.swt2, pywt.swtn],
[pywt.iswt, pywt.iswt2, pywt.iswtn]):
for cwave in ['morl', pywt.DiscreteContinuousWavelet('morl')]:
assert_raises(ValueError, dec_func, data, wavelet=cwave, level=3)
c = dec_func(data, 'db1', level=3)
assert_raises(ValueError, rec_func, c, wavelet=cwave)
def test_error_on_continuous_wavelet():
# A ValueError is raised if a Continuous wavelet is selected
data = np.ones((16, 16))
with warnings.catch_warnings(): # avoid FutureWarning in swt2
warnings.simplefilter('ignore', FutureWarning)
for dec_func, rec_func in zip([pywt.swt, pywt.swt2, pywt.swtn],
[pywt.iswt, pywt.iswt2, pywt.iswtn]):
for cwave in ['morl', pywt.DiscreteContinuousWavelet('morl')]:
assert_raises(ValueError, dec_func, data, wavelet=cwave,
level=3)
c = dec_func(data, 'db1', level=3)
assert_raises(ValueError, rec_func, c, wavelet=cwave)
def wavelet_basis(responses, n_basis, family='db4'):
"""Evaluates Daubechies basis.
Arguments
----------
responses : array
An array of responses in [0, 1].
n_basis : integer
The number of basis functions to evaluate.
family : string
The wavelet family to evaluate.
Returns
-------
numpy matrix
A matrix of Fourier basis functions evaluated at `responses`. Each row
corresponds to a value of `responses`, each column corresponds to a
basis function.
"""
responses = responses.flatten()
n_aux = 15
rez = pywt.DiscreteContinuousWavelet(family).wavefun(n_aux)
if len(rez) == 2:
wavelet, x_grid = rez
else:
_, wavelet, x_grid = rez
wavelet *= np.sqrt(max(x_grid) - min(x_grid))
x_grid = (x_grid - min(x_grid)) / (max(x_grid) - min(x_grid))
def _wave_fun(val):
if val < 0 or val > 1:
return 0.0
return wavelet[np.argmin(abs(val - x_grid))]
n_obs = responses.shape[0]
basis = np.empty((n_obs, n_basis))
basis[:, 0] = 1.0
loc = 0
level = 0
for col in range(1, n_basis):
basis[:, col] = [
2**(level / 2) * _wave_fun(a * 2**level - loc) for a in responses
]
loc += 1
if loc == 2**level:
loc = 0
level += 1
return basis
def cwt_tf(data, scales, wavelet, batch_size, sampling_period=1.):
# accept array_like input; make a copy to ensure a contiguous array
dt = tf.float32
dt_cplx = tf.complex64
if not isinstance(wavelet, (pywt.ContinuousWavelet, pywt.Wavelet)):
wavelet = pywt.DiscreteContinuousWavelet(wavelet)
if np.isscalar(scales):
scales = np.array([scales])
dt_out = dt_cplx if wavelet.complex_cwt else dt
out = []
precision = 10
int_psi, x = pywt.integrate_wavelet(wavelet, precision=precision)
int_psi = np.conj(int_psi) if wavelet.complex_cwt else int_psi
# convert int_psi, x to the same precision as the data
dt_psi = np.complex64 if int_psi.dtype.kind == 'c' else np.float32
int_psi = np.asarray(int_psi, dtype=dt_psi)
x = np.asarray(x, dtype=np.float32)
for i, scale in enumerate(scales):
step = x[1] - x[0]
j = np.arange(scale * (x[-1] - x[0]) + 1) / (scale * step)
j = j.astype(int) # floor
if j[-1] >= int_psi.size:
j = np.extract(j < int_psi.size, j)
int_psi_scale = int_psi[j][::-1]
int_psi_scale_n = np.zeros(
(len(int_psi_scale), data.shape[-1], data.shape[-1]),
dtype=int_psi_scale.dtype)
for c in range(data.shape[-1]):
int_psi_scale_n[:, c, c] = int_psi_scale
conv = tf.nn.convolution(data, int_psi_scale_n, 1, 'SAME')
coef = -tf.math.sqrt(float(scale)) * tf.experimental.numpy.diff(
conv, axis=-2)
if dt_out != dt_cplx:
coef = tf.math.real(coef)
out += [tf.cast(tf.abs(coef), dt_out)]
# frequencies = pywt.scale2frequency(wavelet, scales, precision)
# if np.isscalar(frequencies):
# frequencies = np.array([frequencies])
# frequencies /= sampling_period
return tf.transpose(tf.convert_to_tensor(out, dtype=dt_out),
(1, 0, 2, 3)) #, frequencies
def test_compare_downcoef_coeffs():
rstate = np.random.RandomState(1234)
r = rstate.randn(16)
# compare downcoef against wavedec outputs
for nlevels in [1, 2, 3]:
for wavelet in pywt.wavelist():
wavelet = pywt.DiscreteContinuousWavelet(wavelet)
if isinstance(wavelet, pywt.Wavelet):
max_level = pywt.dwt_max_level(r.size, wavelet.dec_len)
if nlevels <= max_level:
a = pywt.downcoef('a', r, wavelet, level=nlevels)
d = pywt.downcoef('d', r, wavelet, level=nlevels)
coeffs = pywt.wavedec(r, wavelet, level=nlevels)
assert_allclose(a, coeffs[0])
assert_allclose(d, coeffs[1])
def test_dwdtn_idwtn_allwavelets():
rstate = np.random.RandomState(1234)
r = rstate.randn(16, 16)
# test 2D case only for all wavelet types
wavelist = pywt.wavelist()
if 'dmey' in wavelist:
wavelist.remove('dmey')
for wavelet in wavelist:
if isinstance(pywt.DiscreteContinuousWavelet(wavelet), pywt.Wavelet):
for mode in pywt.Modes.modes:
coeffs = pywt.dwtn(r, wavelet, mode=mode)
assert_allclose(pywt.idwtn(coeffs, wavelet, mode=mode),
r,
rtol=1e-7,
atol=1e-7)
]
except AttributeError:
pass
# determine which wavelets to test
wavelist = pywt.wavelist()
if 'dmey' in wavelist:
# accuracy is very low for dmey, so omit it
wavelist.remove('dmey')
# removing wavelets with dwt_possible == False
del_list = []
for wavelet in wavelist:
with warnings.catch_warnings():
warnings.simplefilter('ignore', FutureWarning)
if not isinstance(pywt.DiscreteContinuousWavelet(wavelet),
pywt.Wavelet):
del_list.append(wavelet)
for del_ind in del_list:
wavelist.remove(del_ind)
####
# 1d multilevel dwt tests
####
def test_wavedec():
x = [3, 7, 1, 1, -2, 5, 4, 6]
db1 = pywt.Wavelet('db1')
cA3, cD3, cD2, cD1 = pywt.wavedec(x, db1)
assert_almost_equal(cA3, [8.83883476])
from scipy.signal import stft
import numpy as np
import pywt
scale = ['C', 'C♯', 'D', 'E♭', 'E', 'F', 'F♯', 'G', 'G♯', 'A', 'B♭', 'B']
# Stereo audio; take only the first channel.
rate, data = read("marySongOrig.wav")
data0 = data #[:, 0]
# For wavelet transform, let the input data stream be even.
# Get rid of the first element if the amount of data is odd.
if len(data0) % 2 == 1:
data0 = data0[1:]
# Obtain wavelet.
db1 = pywt.DiscreteContinuousWavelet('db1')
# Denoise the wave using the SureShrink method, where SURE
# is Stein's Unbiased Risk Estimate. Use stationary wavelet
# transform.
# Take the inner product of the original audio with the
# Daubechies wavelet db1. In the time-freq-domain, use soft-
# thresholding to reduce frequencies below a threshold,
# then apply Inverse Stationary Wavelet Transform to get the
# denoised signal. Assume noise is white Gaussian.
output = pywt.swt(data0, db1)
# Measure the threshold.
# Here we use Donoho and Johnstone's method to estimate the
# noise level σ. This is based on the last level of the
import pywt
wavelet = pywt.DiscreteContinuousWavelet('db1')
print(wavelet)
wavelet = pywt.DiscreteContinuousWavelet('gaus1')
print(wavelet)
def fastcwt(data, scales, wavelet, sampling_period=1.0, method='auto'):
"""
Compute the continuous wavelet transform (CWT) and has the same signature
as ``pywt.cwt()`` but is faster for large signals length and scales.
Parameters
----------
signal : array to compute the CWT on
scales: dilatation factors for the CWT
wavelet: wavelet name or pywt.ContinuousWavelet
method=['auto'] | 'conv' | 'fft' for selecting the convolution method
the `'auto'` keyword switch automatically to the best complexity at each
scales. While the `'fft'` and `'conv'` uses `numpy.fft` and `numpy.conv`
respectively.
In practice the `'fft'` method is implemented by using the convolution
theorem which states::
convolve(wav,sig) == ifft(fft(wav)*fft(sig))
Zero padding is adjusted to keep at bay circular convolution side effects.
Example::
%time (coef1, freq1) = fastcwt(np.arange(140000), np.arange(2,200), 'cmorl1-1')
=> CPU times: user 12.6 s, sys: 2.2 s, total: 14.8 s
=> Wall time: 14.9 s
%time (coef1, freq1) = pywt.cwt(np.arange(140000), np.arange(2,200), 'cmorl1-1')
=> CPU times: user 1min 50s, sys: 401 ms, total: 1min 51s
=> Wall time: 1min 51s
"""
# accept array_like input; make a copy to ensure a contiguous array
data = np.array(data)
if not isinstance(wavelet, (pywt.ContinuousWavelet, pywt.Wavelet)):
wavelet = pywt.DiscreteContinuousWavelet(wavelet)
if np.isscalar(scales):
scales = np.array([scales])
dt_out = None # currently keep the 1.0.2 behaviour: TODO fix in/out dtype consistency
if data.ndim == 1:
if wavelet.complex_cwt:
dt_out = complex
out = np.zeros((np.size(scales), data.size), dtype=dt_out)
precision = 10
int_psi, x = pywt.integrate_wavelet(wavelet, precision=precision)
if method in ('auto', 'fft'):
# - to be as large as the sum of data length and and maximum wavelet
# support to avoid circular convolution effects
# - additional padding to reach a power of 2 for CPU-optimal FFT
size_pad = lambda s: 2**np.int(np.ceil(np.log2(s[0] + s[1])))
size_scale0 = size_pad(
(len(data), np.take(scales, 0) * ((x[-1] - x[0]) + 1)))
fft_data = None
elif not method == 'conv':
raise ValueError("method must be in: 'conv', 'fft' or 'auto'")
for i in np.arange(np.size(scales)):
step = x[1] - x[0]
j = np.floor(
np.arange(scales[i] * (x[-1] - x[0]) + 1) / (scales[i] * step))
if np.max(j) >= np.size(int_psi):
j = np.delete(j, np.where((j >= np.size(int_psi)))[0])
int_psi_scale = int_psi[j.astype(np.int)][::-1]
if method == 'conv':
conv = np.convolve(data, int_psi_scale)
else:
size_scale = size_pad((len(data), len(int_psi_scale)))
if size_scale != size_scale0:
# the fft of data changes when padding size changes thus
# it has to be recomputed
fft_data = None
size_scale0 = size_scale
nops_conv = len(data) * len(int_psi_scale)
nops_fft = (
2 + (fft_data is None)) * size_scale * np.log2(size_scale)
if (method == 'fft') or ((method == 'auto') and
(nops_fft < nops_conv)):
if fft_data is None:
fft_data = np.fft.fft(data, size_scale)
fft_wav = np.fft.fft(int_psi_scale, size_scale)
conv = np.fft.ifft(fft_wav * fft_data)
conv = conv[0:len(data) + len(int_psi_scale) - 1]
else:
conv = np.convolve(data, int_psi_scale)
coef = -np.sqrt(scales[i]) * np.diff(conv)
if not np.iscomplexobj(out):
coef = np.real(coef)
d = (coef.size - data.size) / 2.
if d > 0:
out[i, :] = coef[int(np.floor(d)):int(-np.ceil(d))]
elif d == 0.:
out[i, :] = coef
else:
raise ValueError("Selected scale of {} too small.".format(
scales[i]))
frequencies = pywt.scale2frequency(wavelet, scales, precision)
if np.isscalar(frequencies):
frequencies = np.array([frequencies])
for i in np.arange(len(frequencies)):
frequencies[i] /= sampling_period
return out, frequencies
else:
raise ValueError("Only dim == 1 supported")
res = 1 / np.log(2) * (k + np.log(2000 / 30) + gamma(k) + (k + 1) * sum_s)
plt.plot(k, res)
plt.grid()
plt.xlabel('k')
plt.ylabel('H(k)')
plt.show()
#H()
import pywt
from pylab import *
from numpy import *
discrete_wavelets = ['db5', 'sym4', 'coif5', 'haar']
print('discrete_wavelets-%s' % discrete_wavelets)
st = 'db4'
wavelet = pywt.DiscreteContinuousWavelet(st)
print(wavelet)
i = 10
phi, psi, x = wavelet.wavefun(level=i)
#title("График самой вейвлет - функции -%s"%st)
'''plot(x,psi,linewidth=2, label='level=%s'%i)
grid()'''
#legend(loc='best')
title(st)
plt.plot(x, phi, linewidth=2, label='level=%s' % i)
#legend(loc='best')
grid()
show()