def timelag_filter(function, pad=True, index=<NUM_LIT:0>):
def __my_filter(wrapped_f, *args, **kwargs):<EOL><INDENT>'''<STR_LIT>'''<EOL>args = list(args)<EOL>args[index] = recurrence_to_lag(args[index], pad=pad)<EOL>result = wrapped_f(*args, **kwargs)<EOL>return lag_to_recurrence(result)<EOL><DEDENT>return decorator(__my_filter, function)<EOL>
Filtering in the time-lag domain.

    This is primarily useful for adapting image filters to operate on
    `recurrence_to_lag` output.

    Using `timelag_filter` is equivalent to the following sequence of
    operations:

    >>> data_tl = librosa.segment.recurrence_to_lag(data)
    >>> data_filtered_tl = function(data_tl)
    >>> data_filtered = librosa.segment.lag_to_recurrence(data_filtered_tl)

    Parameters
    ----------
    function : callable
        The filtering function to wrap, e.g., `scipy.ndimage.median_filter`

    pad : bool
        Whether to zero-pad the structure feature matrix

    index : int >= 0
        If `function` accepts input data as a positional argument, it should be
        indexed by `index`


    Returns
    -------
    wrapped_function : callable
        A new filter function which applies in time-lag space rather than
        time-time space.


    Examples
    --------

    Apply a 5-bin median filter to the diagonal of a recurrence matrix

    >>> y, sr = librosa.load(librosa.util.example_audio_file())
    >>> chroma = librosa.feature.chroma_cqt(y=y, sr=sr)
    >>> rec = librosa.segment.recurrence_matrix(chroma)
    >>> from scipy.ndimage import median_filter
    >>> diagonal_median = librosa.segment.timelag_filter(median_filter)
    >>> rec_filtered = diagonal_median(rec, size=(1, 3), mode='mirror')

    Or with affinity weights

    >>> rec_aff = librosa.segment.recurrence_matrix(chroma, mode='affinity')
    >>> rec_aff_fil = diagonal_median(rec_aff, size=(1, 3), mode='mirror')

    >>> import matplotlib.pyplot as plt
    >>> plt.figure(figsize=(8,8))
    >>> plt.subplot(2, 2, 1)
    >>> librosa.display.specshow(rec, y_axis='time')
    >>> plt.title('Raw recurrence matrix')
    >>> plt.subplot(2, 2, 2)
    >>> librosa.display.specshow(rec_filtered)
    >>> plt.title('Filtered recurrence matrix')
    >>> plt.subplot(2, 2, 3)
    >>> librosa.display.specshow(rec_aff, x_axis='time', y_axis='time',
    ...                          cmap='magma_r')
    >>> plt.title('Raw affinity matrix')
    >>> plt.subplot(2, 2, 4)
    >>> librosa.display.specshow(rec_aff_fil, x_axis='time',
    ...                          cmap='magma_r')
    >>> plt.title('Filtered affinity matrix')
    >>> plt.tight_layout()