xnn.dnn.models.hdnnp.default_symmetry_functions#

xnn.dnn.models.hdnnp.default_symmetry_functions(species, cutoff, n_radial=6, angular=True)[source]#

A generic symmetry-function set: radial and angular functions for every element.

Radial type 2 functions centred at zero with widths from the cutoff down to cutoff / n_radial (eta = (m / cutoff)^2, m = 1 .. n_radial) for every (central, neighbour) element pair, and angular type 3 functions with eta = 1 / cutoff^2, lambda = +-1 and zeta = 1, 4 for every central element and unordered neighbour pair, all under one cosine cutoff.

Parameters:

species (sequence of int) – Atomic numbers.
cutoff (float) – The cutoff radius.
n_radial (int, optional) – Radial functions per element pair, by default 6.
angular (bool, optional) – Include the angular functions, by default True.

Returns:

The cutoffs and functions of AtomCenteredSymmetryFunctions.

Return type:

(list of dict, list of dict)