g2fplanck.m

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Returns magnetic field gradient operators within the Fokker-Planck formalism used in the imaging module of Spinach.

Syntax

    G=g2fplanck(spin_system,parameters)

Description

The cell array contains {Gx,Gy,Gz}, which should simply be added to the Hamiltonian with appropriate coefficients. Gradients are assumed to be linear and centered on the middle of the sample.

Arguments

  parameters.dims    - a vector with one, two or three 
                       elements giving the dimensions
                       of the box, metres

  parameters.npts    - a vector with one, two or three
                       elements giving number of points
                       in each dimension of the box

Outputs

  G - a cell array with the three gradient operators 
      ordered as {Gx,Gy,Gz}, normalised to 1 T/m, empty
      matrices for non-exitent dimensions

Notes

1. The direct product order is Z(x)Y(x)X(x)Spin, this corresponds to a column-wise vectorization of a 3D array with dimensions ordered as [X Y Z].

2. Polyadic objects are returned, use polyadic/inflate.m to get the corresponding sparse matrix.

See also

v2fplanck.m, hydrodynamics.m, imaging.m


Version 2.1, authors: Ilya Kuprov, Ahmed Allami