class ProxNest.operators.wavelet_operators.db_wavelets(wav, levels, shape, axes=None)

Constructs a linear operator for abstract Daubechies Wavelets.

Notes

Stripped back version of optimus-primal linear operator.

__init__(wav, levels, shape, axes=None)

Initialises Daubechies Wavelet linear operator class.

Parameters

• wav (string) – Wavelet type (see https://tinyurl.com/5n7wzpmb).

• levels (list[int]) – Wavelet levels (scales) to consider.

• shape (list[int]) – Dimensionality of input to wavelet transform.

• axes (int) – Which axes to perform wavelet transform (default = all axes).

Raises

ValueError – Raised when levels are not positive definite.

adj_op(x)

Evaluates the forward adjoint abstract wavelet transform of \(x\).

Parameters

x (np.ndarray) – Array to adjoint wavelet transform.

Returns

Array of pixel-space coefficients.

Return type

np.ndarray

dir_op(x)

Evaluates the forward abstract wavelet transform of \(x\).

Parameters

x (np.ndarray) – Array to wavelet transform.

Raises

ValueError – Raised when the shape of x is not even in every dimension.

Returns

Flattened array of wavelet coefficients.

Return type

np.ndarray