Uses MiniBatch k-means clustering to cluster matrix into groups.

    Each cluster of rows is then sorted by `scorefunc` -- by default, the max
    peak height when all rows in a cluster are averaged, or
    cluster.mean(axis=0).max().

    Returns the index that will sort the rows of `x` and a list of "breaks".
    `breaks` is essentially a cumulative row count for each cluster boundary.
    In other words, after plotting the array you can use axhline on each
    "break" to plot the cluster boundary.

    If `k` is a list or tuple, iteratively try each one and select the best
    with the lowest mean distance from cluster centers.

    :param x: Matrix whose rows are to be clustered
    :param k: Number of clusters to create or a list of potential clusters; the
        optimum will be chosen from the list
    :param row_key:
        Optional function to act as a sort key for sorting rows within
        clusters.  Signature should be `scorefunc(a)` where `a` is a 1-D NumPy
        array.
    :param cluster_key:
        Optional function for sorting clusters.  Signature is `clusterfunc(a)`
        where `a` is a NumPy array containing all rows of `x` for cluster `i`.
        It must return a single value.

def new_clustered_sortind(x, k=10, row_key=None, cluster_key=None):
    """
    Uses MiniBatch k-means clustering to cluster matrix into groups.

    Each cluster of rows is then sorted by `scorefunc` -- by default, the max
    peak height when all rows in a cluster are averaged, or
    cluster.mean(axis=0).max().

    Returns the index that will sort the rows of `x` and a list of "breaks".
    `breaks` is essentially a cumulative row count for each cluster boundary.
    In other words, after plotting the array you can use axhline on each
    "break" to plot the cluster boundary.

    If `k` is a list or tuple, iteratively try each one and select the best
    with the lowest mean distance from cluster centers.

    :param x: Matrix whose rows are to be clustered
    :param k: Number of clusters to create or a list of potential clusters; the
        optimum will be chosen from the list
    :param row_key:
        Optional function to act as a sort key for sorting rows within
        clusters.  Signature should be `scorefunc(a)` where `a` is a 1-D NumPy
        array.
    :param cluster_key:
        Optional function for sorting clusters.  Signature is `clusterfunc(a)`
        where `a` is a NumPy array containing all rows of `x` for cluster `i`.
        It must return a single value.
    """
    try:
        from sklearn.cluster import MiniBatchKMeans
    except ImportError:
        raise ImportError('please install scikits.learn for '
                          'clustering.')

    # If integer, do it once and we're done
    if isinstance(k, int):
        best_k = k

    else:
        mean_dists = {}
        for _k in k:
            mbk = MiniBatchKMeans(init='k-means++', n_clusters=_k)
            mbk.fit(x)
            mean_dists[_k] = mbk.transform(x).mean()
        best_k = sorted(mean_dists.items(), key=lambda x: x[1])[-1][0]

    mbk = MiniBatchKMeans(init='k-means++', n_clusters=best_k)
    mbk.fit(x)
    k = best_k
    labels = mbk.labels_
    scores = np.zeros(labels.shape, dtype=float)

    if cluster_key:
        # It's easier for calling code to provide something that operates on
        # a cluster level, but here it's converted to work on a label level
        # that looks in to the array `x`.
        def _cluster_key(i):
            return cluster_key(x[labels == i, :])
        sorted_labels = sorted(range(k), key=_cluster_key)
    else:
        # Otherwise just use them as-is.
        sorted_labels = range(k)

    if row_key:
        # Again, easier to provide a function to operate on a row.  But here we
        # need it to accept an index
        def _row_key(i):
            return row_key(x[i, :])

    final_ind = []
    breaks = []
    pos = 0
    for label in sorted_labels:
        # which rows in `x` have this label
        label_inds = np.nonzero(labels == label)[0]
        if row_key:
            label_sort_ind = sorted(label_inds, key=_row_key)
        else:
            label_sort_ind = label_inds
        for li in label_sort_ind:
            final_ind.append(li)
        pos += len(label_inds)
        breaks.append(pos)

    return np.array(final_ind), np.array(breaks)