MRIStackedNUFFTGPU#

class mrinufft.operators.stacked.MRIStackedNUFFTGPU(samples, shape, smaps, n_coils=1, n_batchs=1, n_trans=1, z_index='auto', squeeze_dims=False, smaps_cached=False, density=False, backend='cufinufft', **kwargs)[source]#

Bases: MRIStackedNUFFT

Stacked NUFFT Operator for MRI using GPU only backend.

This requires cufinufft to be installed.

Parameters:
  • samples (array-like) – Sample locations in a 2D kspace

  • shape (tuple) – Shape of the image.

  • z_index (array-like) – Cartesian z index of masked plan. if “auto” the z_index is computed from the samples, if they are 3D, using the last coordinate.

  • smaps (array-like) – Sensitivity maps.

  • n_coils (int) – Number of coils.

  • n_batchs (int) – Number of batchs.

  • **kwargs (dict) – Additional arguments to pass to the backend.

Methods

__init__

adj_op

Adjoint operator.

check_shape

Validate the shapes of the image or k-space data against operator shapes.

compute_density

Compute the density compensation weights and set it.

compute_smaps

Compute the sensitivity maps and set it.

data_consistency

Compute the gradient data consistency.

get_lipschitz_cst

Return the Lipschitz constant of the operator.

make_autograd

Make a new Operator with autodiff support.

op

Forward operator.

with_autograd

Return a Fourier operator with autograd capabilities.

with_off_resonance_correction

Return a new operator with Off Resonnance Correction.

Attributes

autograd_available

available

backend

cpx_dtype

Return complex floating precision of the operator.

density

Density compensation of the operator.

dtype

Return dtype.

interfaces

n_coils

Number of coils for the operator.

n_samples

Return number of samples.

ndim

Number of dimensions in image space of the operator.

norm_factor

Norm factor of the operator.

samples

Return samples as a N_slice x N_samples x 3 array.

shape

Shape of the image space of the operator.

smaps

Sensitivity maps of the operator.

uses_density

Return True if the operator uses density compensation.

uses_sense

Return True if the operator uses sensitivity maps.

property norm_factor#

Norm factor of the operator.

static _fftz(data)[source]#

Apply FFT on z-axis.

static _ifftz(data)[source]#

Apply IFFT on z-axis.

op(data, ksp=None)[source]#

Forward operator.

adj_op(coeffs, img=None)[source]#

Adjoint operator.

get_lipschitz_cst(max_iter, **kwargs)[source]#

Return the Lipschitz constant of the operator.

Parameters:
  • max_iter (int) – Number of iteration to perform to estimate the Lipschitz constant.

  • kwargs – Extra kwargs for the cufinufft operator.

Returns:

Lipschitz constant of the operator.

Return type:

float