def Calc_instantaneous_ET_fraction(LE_inst, rn_inst, g_inst):
    """
    Function to calculate the evaporative fraction
    """
    EF_inst = LE_inst / (rn_inst - g_inst)
    EF_inst = EF_inst.clip(0.0, 1.8)
    EF_inst[LE_inst < 0] = 0
    return EF_inst
