def getMass(generalData):
    """Computes mass of unit cell contents
    
    :param dict generalData: The General dictionary in Phase
    
    :returns: float mass: Crystal unit cell mass in AMU.
    
    """
    mass = 0.0
    for i, elem in enumerate(generalData['AtomTypes']):
        mass += generalData['NoAtoms'][elem] * generalData['AtomMass'][i]
    return max(mass, 1.0)
