Get a vector flds data.

    Parameters:
    -----------

    d -- flds data.
    s -- key for the data.

def getvector(d,s):
    '''
    Get a vector flds data.

    Parameters:
    -----------

    d -- flds data.
    s -- key for the data.
    '''
    return np.array([d[s+"x"],d[s+"y"],d[s+"z"]]);