# overwound.m

From Spinach Documentation Wiki

Checks if a Fokker-Planck state vector has any spatial frequencies that its spatial grid is dangerously close to misrepresenting due to insufficient point count.

## Syntax

overwound(rho,spc_dim,spn_dim)

## Arguments

rho - Fokker-Planck state vector or a bookshelf stack thereof spc_dim - spatial dimensions of the Fokker- Planck problem, [X Y Z] spn_dim - spin dimension of the Fokker- Planck problem

## Outputs

figures and diagnostic messages to the console

## Examples

An example of the spatial frequency distribution after the first chirp pulse of the psyche.m pulse sequence appears below.

In this case, the grid point count must be increased because some frequencies are folded.

## Notes

If you are running spatial dynamics, such as diffusion and and flow, with finite difference derivative operators, the spatial grid point count should be set to several times the minimum Nyquist value.

## See also

imaging.m, hydrodynamics.m, g2fplanck.m, phan2fpl.m, fpl2phan.m

*Version 2.3, authors: Ilya Kuprov*