coulomb_kmc.kmc_dirichlet_boundary module

Module to handle Dirichlet boundary conditions. By using mirror charges mirror “plate like” boundary conditions are achieved.

This implementation allows for planes where the field is zero at either end and the middle of a domain in a direction.

class coulomb_kmc.kmc_dirichlet_boundary.MirrorChargeSystem(dims_to_zero, state, position_name, charge_name, id_name)

Bases: object

Class to create a cubic system of mirror charges from an initial system. The intent is that the potential field on the boundaries of the original system are zero. The current implementation only allows for one direction to have a zero field boundary condition.

This class is initialised with a set of positions, charges and globals ids to create a mirror charge system from. It is assumed that the global ids are in [0, N-1] for N charges. The new global ids are in [N, 2N-1].

The new state contains a new ParticleDat (ncomp=2, dtype=c_int64) that indicates if a particle is a mirror charge or an “original” charge.

The 0-th component points to the new mirror for the original positions

mirror_map[:N:, 0] = new_ids[N:2*N:, 0]
# and to the original id for the mirrors
mirror_map[N:2*N:, 0] = new_ids[:N:, 0]

The 1-th component indicates if the charge is a mirror.

mirror_maps[:N:, 1] = MIRROR_ORIG
if   dims_to_zero[0]: flag = MIRROR_X_REFLECT
elif dims_to_zero[1]: flag = MIRROR_Y_REFLECT
elif dims_to_zero[2]: flag = MIRROR_Z_REFLECT
mirror_maps[N:2*N:, 1] = flag
Parameters

  • dims_to_zero – xyz tuple of directions to make zero on boundary. e.g. (True, False, False) for x-direction.

  • state – initial state to tile and reflect.

  • position_name (str) – Name of PositionDat instance in passed state.

  • charge_name (str) – Name of ParticleDat (ncomp=1, dtype=c_double) to use for charges.

  • id_name (str) – Name of ParticleDat (ncomp=1, dtype=c_int64) to use for global ids.

mirror_state

Created state with 2N particles. PositionDat named position_name, ParticleDat named charge_name, ParticleDat named id_name and ParticleDat named “mirror_map”.