# ngridpts.m

From Spinach Documentation Wiki

Estimates the minimum number of spatial grid points necessary to have a valid treatment of gradient driven experiments with explicit digitization of spatial dimensions.

## Syntax

n=ngridpts(grad_amps,grad_durs,isotope,max_coh_order)

## Description

The function checks the Larmor condition for the tightest possible gradient spiral.

## Arguments

grad_amps - a row vector of all gradient amplitudes in the sequence, T/m grad_durs - a row vector of all gradient durations in the sequence, s isotope - the highest magnetogyric ratio isotope in the spin system, e.g. '1H' max_coh_order - maximum order of coherence (either positive or negative) expected during the experiment being simulated sample_size - spatial extent of the sample, m

## Outputs

n - the minimum recommended number of discretisation points

## Notes

The function returns the minimum number of points, it may in practice be necessary to have several times the number, depending on your accuracy requirements.

## See also

imaging.m, fdmat.m, hydrodynamics.m

*Version 2.1, authors: Ilya Kuprov*