PyWavelets 0.4.0 Release Notes¶
Contents
PyWavelets 0.4.0 is the culmination of 6 months of work. In addition to several new features, some changes and deprecations have been made to streamline the API.
This release requires Python 2.6, 2.7 or 3.3-3.5 and NumPy 1.6.2 or greater.
Highlights of this release include:
1D and 2D inverse stationary wavelet transforms
Substantially faster 2D and nD discrete wavelet transforms
Complex number support
nD versions of the multilevel DWT and IDWT
New features¶
1D and 2D inverse stationary wavelet transforms¶
1D (iswt) and 2D (iswt2) inverse stationary wavelet transforms were
added. These currently only support even length inputs.
Faster 2D and nD wavelet transforms¶
The multidimensional DWT and IDWT code was refactored and is now an order of
magnitude faster than in previous releases. The following functions benefit:
dwt2, idwt2, dwtn, idwtn.
Complex floating point support¶
64 and 128-bit complex data types are now supported by all wavelet transforms.
nD implementation of the multilevel DWT and IDWT¶
The existing 1D and 2D multilevel transforms were supplemented with an nD implementation.
Wavelet transforms can be applied along a specific axis/axes¶
All wavelet transform functions now support explicit specification of the axis or axes upon which to perform the transform.
Example Datasets¶
Two additional 2D grayscale images were added (camera, ascent). The
previously existing 1D ECG data (ecg) and the 2D aerial image (aero)
used in the demos can also now be imported via functions defined in
pywt.data (e.g. camera = pywt.data.camera())
Deprecated features¶
A number of functions have been renamed, the old names are deprecated and will be removed in a future release:
intwave, renamed tointegrate_waveletcentrfrq, renamed tocentral_frequencyscal2frq, renamed toscale2frequencyorthfilt, renamed toorthogonal_filter_bank
Integration of general signals (i.e. not wavelets) with integrate_wavelet
is deprecated.
The MODES object and its attributes are deprecated. The new name is
Modes, and the attribute names are expanded:
zpd, renamed tozerocpd, renamed toconstantsp1, renamed tosmoothsym, renamed tosymmetricppd, renamed toperiodicper, renamed toperiodization
Backwards incompatible changes¶
idwt no longer takes a correct_size parameter. As a consequence,
idwt2 inputs must match exactly in length. For multilevel transforms, where
arrays differing in size by one element may be produced, use the waverec
functions from the multilevel module instead.
Bugs Fixed¶
float32 inputs were not always respected. All transforms now return float32 outputs when called using float32 inputs.
Incorrect detail coefficients were returned by downcoef when level > 1.
Other changes¶
Much of the API documentation is now autogenerated from the corresponding function docstrings. The numpydoc sphinx extension is now needed to build the documentation.
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