spheropack.analysis.rattlers#

spheropack.analysis.rattlers(packing, tol=1e-05, method='auto', force_threshold=0.001)#

Boolean mask of rattlers: spheres that carry no force in a jammed packing.

Parameters:

  • method (str) – "force": a sphere is a rattler when its time-averaged collision pressure in the last measurement window (Packing.sphere_pressure) is below force_threshold times the median. This is the physical definition: the collision impulses of an event-driven simulation are the contact forces. "contacts": spheres with fewer than dim + 1 contacts (see contacts() for tol) are removed together with their contacts, repeatedly, until all remaining spheres have at least dim + 1. It needs no dynamics but cannot detect spheres whose contacts do not balance. "auto": "force" when per-sphere pressures are available.

  • packing (Packing)

  • tol (float)

  • force_threshold (float)

Return type:

ndarray