ValueError call wrong when using energies only

In loss.py, you have the error call at the end of this block.

I don't think it can coexist with option 1 where S=1 and not S=3N+1...

    1) If `use_energy == True` and `use_forces == False`, then `S = 1`.
    `prediction[0]` is the potential energy computed by the calculator, and
    `reference[0]` is the reference energy.

    2) If `use_energy == False` and `use_forces == True`, then `S = 3N`.
    `prediction[3*i+0]`, `prediction[3*i+1]`, and `prediction[3*i+2]` are the
    x, y, and z component of the forces on atom i in the configuration, respecrively.
    Correspondingly, `reference` is the 3N concatenated reference forces.

    3) If `use_energy == True` and `use_forces == True`, then `S = 3N + 1`.
    `prediction[0]` is the potential energy computed by the calculator, and
    `reference[0]` is the reference energy.
    `prediction[3*i+1]`, `prediction[3*i+2]`, and `prediction[3*i+3]` are the
    x, y, and z component of the forces on atom i in the configuration, respecrively.
    Correspondingly, `reference` is the 3N concatenated reference forces.
    """

    if len(prediction) != 3 * natoms + 1:
        raise ValueError("len(prediction) != 3N+1, where N is the number of atoms.")

openkim / kliff

ValueError call wrong when using energies only #1