Function _nnmark

stumpy/floss.py:13–47

Count the number of nearest neighbor overhead crossings or arcs. Parameters ---------- I : numpy.ndarray Matrix profile indices Returns ------- nnmark : numpy.ndarray Counts of nearest neighbor overheard crossings or arcs. Notes ----- DOI:

(I)

def _nnmark(I):
    """
    Count the number of nearest neighbor overhead crossings or arcs.

    Parameters
    ----------
    I : numpy.ndarray
        Matrix profile indices

    Returns
    -------
    nnmark : numpy.ndarray
        Counts of nearest neighbor overheard crossings or arcs.

    Notes
    -----
    DOI: 10.1109/ICDM.2017.21 <https://www.cs.ucr.edu/~eamonn/Segmentation_ICDM.pdf>`__

    See Table I

    This is a fast and vectorized implementation of the nnmark algorithm.
    """
    I = I.astype(np.int64)

    # Replace index values that are less than zero with its own positional index
    idx = np.argwhere(I < 0).flatten()
    I[idx] = idx

    k = I.shape[0]
    i = np.arange(k, dtype=np.int64)

    nnmark = np.bincount(np.minimum(i, I), minlength=k)
    nnmark -= np.bincount(np.maximum(i, I), minlength=k)

    return nnmark.cumsum()


def _iac(