get_pair_displacements

torch_sim.transforms.get_pair_displacements(*, positions, cell=None, pbc=True, pairs=None, shifts=None)

Compute displacement vectors and distances between atom pairs.

Parameters:

• positions (torch.Tensor) – Atomic positions [N, 3].

• cell (Optional[torch.Tensor]) – Unit cell matrix [3, 3].

• pbc (bool) – Whether to apply periodic boundary conditions.

• pairs (Optional[Tuple[torch.Tensor, torch.Tensor]]) – (i, j) indices for specific pairs to compute.

• shifts (Optional[torch.Tensor]) – Shift vectors for periodic images [n_pairs, 3].

Returns:

• Displacement vectors [n_pairs, 3].

• Distances [n_pairs].

Return type:

tuple[Tensor, Tensor]