# Fixed cutoff method¶

The most common method to calculate the nearest neighbors of an atom is using a cutoff radius. The neighborhood of an atom for calculation of Steinhardt’s parameters [1] is often carried out using this method. Commonly, a cutoff is selected as the first minimum of the radial distribution functions. Once a cutoff is selected, the neighbors of an atom are those that fall within this selected radius. The following code snippet will use the cutoff method to calculate neighbors. Please check the examples section for basic use of the module. In this example, conf.dump is assumed to be the input configuration of the system. A cutoff radius of 3 is assumed for calculation of neighbors.

import pyscal.core as pc
sys = pc.System()