Creates a three-dimesional voxel grid. For each voxel, generates volume fraction of the
anisotropic component, diffusivity, and orientation of the anisotropic component, in
accordance with the ball and stick method descibed by Behrens et al in MRM(50) 1077-1088,
2003. The orientation for each voxel is the same as the orientation of the radial line of
a circle passing through the centre of the voxel. The position of the centre of the
circle relative to the centre of the voxel grid is specified by centredist.
EXAMPLES
Create a voxel grid with dimensions 6 imes 8 imes 4 units, with circle at distance of
5 units from the centre of the voxel grid, volume fraction of 0.75 and diffusivity of
1.5E-9 for each voxel and store the output in testFan.Bdouble: