xnn.ffnn.models.geometry#
Shared bonded-term geometry for fixed-topology force fields.
Minimum-image displacement vectors, the dihedral cosine and a
differentiable-at-zero geometric mean, used by every fixed-topology model
(OPLS, DREIDING). All functions operate on a batched
AtomicGraph plus explicit atom-index tensors, so
bonded terms are correct for molecules wrapped across periodic boundaries
while gradients still flow to positions and cell.
Functions
|
Cosine of the dihedral angle over each atom quadruple. |
|
Geometric mean with a differentiable zero (for zero-LJ hydrogens). |
|
Minimum-image displacement vectors |