def differences(lattice_params, ref):
    """
    Returns relaxed structures with the parameters from the fitted potential implemented.

    Args:
        lattice_params (np.array): lattice parameters (a,b,c) and volume of fitted MD parameters.
        ref (np.array): lattice parameters (a,b,c) and volume of DFT reference values.

    Returns:
        np.array: Percentage differences between MD (lattice_params) and DFT (ref) lattice parameters.
    """
    return ((lattice_params-ref)/ref)*100