Velocity

Atomic velocities are associated with the "velocity" or "velocity/<variant>" name (see Variants), and must have the following metadata:

Metadata for "velocity"

Metadata	Names	Description
keys	"_"	the keys must have a single dimension named "_", with a single entry set to 0. The "velocity" quantity is always represented as a metatensor.torch.TensorMap with a single block.
samples	["system", "atom"]	the samples must be named ["system", "atom"], since "velocity" is always per-atom. "system" must range from 0 to the number of systems given as input to the model. "atom" must range between 0 and the number of atoms/particles in the corresponding system. If selected_atoms is provided, then only the selected atoms for each system should be part of the samples.
components	"xyz"	The "velocity" quantity must have a single component dimension named "xyz", with three entries set to 0, 1, and 2. The position is always a 3D vector, and the order of the components is x, y, z.
properties	"velocity"	The "velocity" quantity must have a single property dimension named "velocity", with a single entry set to 0.

The following simulation engine can provide "velocity" as inputs to the models:

ASE

i-PI