pylops.signalprocessing.DWT#
- class pylops.signalprocessing.DWT(dims, axis=-1, wavelet='haar', level=1, dtype='float64', name='D')[source]#
One dimensional Wavelet operator.
Apply 1D-Wavelet Transform along an
axis
of a multi-dimensional array of sizedims
.Note that the Wavelet operator is an overload of the
pywt
implementation of the wavelet transform. Refer to https://pywavelets.readthedocs.io for a detailed description of the input parameters.- Parameters
- dims
int
ortuple
Number of samples for each dimension
- axis
int
, optional New in version 2.0.0.
Axis along which DWT is applied
- wavelet
str
, optional Name of wavelet type. Use
pywt.wavelist(kind='discrete')
for a list of available wavelets.- level
int
, optional Number of scaling levels (must be >=0).
- dtype
str
, optional Type of elements in input array.
- name
str
, optional New in version 2.0.0.
Name of operator (to be used by
pylops.utils.describe.describe
)
- dims
- Raises
- ModuleNotFoundError
If
pywt
is not installed- ValueError
If
wavelet
does not belong topywt.families
Notes
The Wavelet operator applies the multilevel Discrete Wavelet Transform (DWT) in forward mode and the multilevel Inverse Discrete Wavelet Transform (IDWT) in adjoint mode.
Wavelet transforms can be used to compress signals and present a key advantage over Fourier transforms in that they captures both frequency and location information in time. Consider using this operator as sparsifying transform when using L1 solvers.
- Attributes
Methods
__init__
(dims[, axis, wavelet, level, ...])adjoint
()apply_columns
(cols)Apply subset of columns of operator
cond
([uselobpcg])Condition number of linear operator.
conj
()Complex conjugate operator
div
(y[, niter, densesolver])Solve the linear problem \(\mathbf{y}=\mathbf{A}\mathbf{x}\).
dot
(x)Matrix-matrix or matrix-vector multiplication.
eigs
([neigs, symmetric, niter, uselobpcg])Most significant eigenvalues of linear operator.
matmat
(X)Matrix-matrix multiplication.
matvec
(x)Matrix-vector multiplication.
reset_count
()Reset counters
rmatmat
(X)Matrix-matrix multiplication.
rmatvec
(x)Adjoint matrix-vector multiplication.
todense
([backend])Return dense matrix.
toimag
([forw, adj])Imag operator
toreal
([forw, adj])Real operator
tosparse
()Return sparse matrix.
trace
([neval, method, backend])Trace of linear operator.
transpose
()
Examples using pylops.signalprocessing.DWT
#
Dual-Tree Complex Wavelet Transform