def scaler_mm(group):
    """
    对输入的group进行(group - group.min()) / (group.max() - group.min())
            eg.
                pd.DataFrame对象

                input:
                            tsla	bidu	noah	sfun	goog	vips	aapl
                2014-07-25	223.57	226.50	15.32	12.110	589.02	21.349	97.67
                2014-07-28	224.82	225.80	16.13	12.450	590.60	21.548	99.02
                2014-07-29	225.01	220.00	16.75	12.220	585.61	21.190	98.38
                2014-07-30	228.92	219.13	16.83	11.780	587.42	21.185	98.15

                output:
                            tsla	bidu	noah	sfun	goog	vips	aapl
                2014-07-25	0.5612	0.7979	0.0973	0.9493	0.3396	0.5597	0.1718
                2014-07-28	0.5700	0.7920	0.1305	0.9913	0.3452	0.5699	0.2035
                2014-07-29	0.5713	0.7428	0.1559	0.9629	0.3276	0.5517	0.1885
                2014-07-30	0.5988	0.7354	0.1592	0.9084	0.3340	0.5514	0.1831

                pd.Series对象

                input:
                2014-07-25    223.57
                2014-07-28    224.82
                2014-07-29    225.01
                2014-07-30    228.92
                2014-07-31    223.30

                output:
                2014-07-25    0.5612
                2014-07-28    0.5700
                2014-07-29    0.5713
                2014-07-30    0.5988
                2014-07-31    0.5593


                np.array

                input:
                array([[ 223.57 ,  226.5  ,   15.32 , ...,  589.02 ,   21.349,   97.67 ],
               [ 224.82 ,  225.8  ,   16.13 , ...,  590.6  ,   21.548,   99.02 ],
               [ 225.01 ,  220.   ,   16.75 , ...,  585.61 ,   21.19 ,   98.38 ],
               ...,
               [ 222.27 ,  160.88 ,   25.5  , ...,  742.74 ,   13.51 ,   98.66 ],
               [ 230.01 ,  160.25 ,   25.57 , ...,  739.77 ,   13.39 ,   97.34 ],
               [ 225.93 ,  163.09 ,   24.75 , ...,  740.92 ,   13.655,   97.76 ]])

               output:

                array([[ 0.2838,  0.2876,  0.0141, ...,  0.7571,  0.0219,  0.1207],
                       [ 0.2854,  0.2867,  0.0151, ...,  0.7591,  0.0222,  0.1225],
                       [ 0.2857,  0.2792,  0.0159, ...,  0.7527,  0.0217,  0.1217],
                       ...,
                       [ 0.2821,  0.2026,  0.0273, ...,  0.9561,  0.0117,  0.122 ],
                       [ 0.2921,  0.2018,  0.0274, ...,  0.9523,  0.0116,  0.1203],
                       [ 0.2868,  0.2055,  0.0263, ...,  0.9538,  0.0119,  0.1209]])

    :param group: pd.DataFrame对象, pd.Series对象, np.array对象
    """
    return (group - group.min()) / (group.max() - group.min())
