tfmri.linalg.LinearOperatorWavelet

class LinearOperatorWavelet(domain_shape, wavelet, mode='symmetric', level=None, axes=None, dtype=tf.float32, name='LinearOperatorWavelet')[source]

Bases: tensorflow_mri.python.util.linalg_imaging.LinearOperator

Linear operator representing a wavelet decomposition matrix.

Parameters

  • domain_shape – A 1D tf.Tensor or a list of int. The domain shape of this linear operator.

  • wavelet –

    A str or a `pywt.Wavelet`_, or a list thereof. When passed a list, different wavelets are applied along each axis in axes.

  • mode –

    A str. The padding or signal extension mode. Must be one of the values supported by tfmri.signal.wavedec. Defaults to 'symmetric'.

  • level –

    An int >= 0. The decomposition level. If None (default), the maximum useful level of decomposition will be used (see tfmri.signal.max_wavelet_level).

  • axes –

    A list of int. The axes over which the DWT is computed. Axes refer only to domain dimensions without regard for the batch dimensions. Defaults to None (all domain dimensions).

  • dtype – A tf.dtypes.DType. The data type for this operator. Defaults to float32.

  • name –

    A str. A name for this operator.

Initialize the LinearOperator. (deprecated arguments)

Deprecated: SOME ARGUMENTS ARE DEPRECATED: (graph_parents). They will be removed in a future version. Instructions for updating: Do not pass graph_parents. They will no longer be used.

This is a private method for subclass use. Subclasses should copy-paste this ``__init__`` documentation.

Parameters

  • dtype – The type of the this LinearOperator. Arguments to matmul and solve will have to be this type.

  • graph_parents – (Deprecated) Python list of graph prerequisites of this LinearOperator Typically tensors that are passed during initialization

  • is_non_singular – Expect that this operator is non-singular.

  • is_self_adjoint – Expect that this operator is equal to its hermitian transpose. If dtype is real, this is equivalent to being symmetric.

  • is_positive_definite – Expect that this operator is positive definite, meaning the quadratic form x^H A x has positive real part for all nonzero x. Note that we do not require the operator to be self-adjoint to be positive-definite. See: https://en.wikipedia.org/wiki/Positive-definite_matrix#Extension_for_non-symmetric_matrices

  • is_square – Expect that this operator acts like square [batch] matrices.

  • name – A name for this LinearOperator.

  • parameters – Python dict of parameters used to instantiate this LinearOperator.

Raises

  • ValueError –

    If any member of graph_parents is None or not a Tensor.

  • ValueError – If hints are set incorrectly.