Explanations

Explanations#

The concepts behind bartorch, one page each, from the call into BART to learned reconstruction and performance. Exact interfaces are in API reference, and complete workflows in the examples.

Page

Contents

Execution model

Tools, apps and operators over one embedded BART; errors, devices and threads

Data layout

Tensor axes as BART dimensions, Fourier conventions, trajectory units and file formats

Encoding operators

MRI forward operator, operator algebra, the plan it is lowered into

Non-Cartesian transform

NUFFT, density compensation, Toeplitz normal

Regularizers

Penalties and their proximal operators

Solvers

Choice of iteration, step size and regularization weight

Model-based reconstruction

Nonlinear forward models, IRGNM, joint coil estimation and parameter maps

Learned reconstruction

Gradients through operators and solvers; networks inside a reconstruction

Performance

Devices, precision, threads and the libraries behind BLAS, LAPACK and the FFT