
    M/Ph                         d Z ddlZddZdS )a  Collection of alternative implementations for time series analysis


>>> signal.fftconvolve(x,x[::-1])[len(x)-1:len(x)+10]/x.shape[0]
array([  2.12286549e+00,   1.27450889e+00,   7.86898619e-02,
        -5.80017553e-01,  -5.74814915e-01,  -2.28006995e-01,
         9.39554926e-02,   2.00610244e-01,   1.32239575e-01,
         1.24504352e-03,  -8.81846018e-02])
>>> sm.tsa.stattools.acovf(X, fft=True)[:order+1]
array([  2.12286549e+00,   1.27450889e+00,   7.86898619e-02,
        -5.80017553e-01,  -5.74814915e-01,  -2.28006995e-01,
         9.39554926e-02,   2.00610244e-01,   1.32239575e-01,
         1.24504352e-03,  -8.81846018e-02])

>>> import nitime.utils as ut
>>> ut.autocov(s)[:order+1]
array([  2.12286549e+00,   1.27450889e+00,   7.86898619e-02,
        -5.80017553e-01,  -5.74814915e-01,  -2.28006995e-01,
         9.39554926e-02,   2.00610244e-01,   1.32239575e-01,
         1.24504352e-03,  -8.81846018e-02])
    NTc                    ddl m} t          j        |           } |r| |                                 z
  } |                    | | ddd                   t          |           dz
  t          |           dz            | j        d         z   dS )a_  autocovariance function with call to fftconvolve, biased

    Parameters
    ----------
    x : array_like
        timeseries, signal
    demean : bool
        If true, then demean time series

    Returns
    -------
    acovf : ndarray
        autocovariance for data, same length as x

    might work for nd in parallel with time along axis 0

    r   )signalN   
   )scipyr   npasarraymeanfftconvolvelenshape)xdemeanr   s      _/var/www/html/test/jupyter/venv/lib/python3.11/site-packages/statsmodels/sandbox/archive/tsa.py	acovf_fftr      s    $ 

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