Module « scipy.cluster.hierarchy »

Fonction to_mlab_linkage - module scipy.cluster.hierarchy

Signature de la fonction to_mlab_linkage

def to_mlab_linkage(Z) 

Description

to_mlab_linkage.__doc__

    Convert a linkage matrix to a MATLAB(TM) compatible one.

    Converts a linkage matrix ``Z`` generated by the linkage function
    of this module to a MATLAB(TM) compatible one. The return linkage
    matrix has the last column removed and the cluster indices are
    converted to ``1..N`` indexing.

    Parameters
    ----------
    Z : ndarray
        A linkage matrix generated by ``scipy.cluster.hierarchy``.

    Returns
    -------
    to_mlab_linkage : ndarray
        A linkage matrix compatible with MATLAB(TM)'s hierarchical
        clustering functions.

        The return linkage matrix has the last column removed
        and the cluster indices are converted to ``1..N`` indexing.

    See Also
    --------
    linkage : for a description of what a linkage matrix is.
    from_mlab_linkage : transform from Matlab to SciPy format.

    Examples
    --------
    >>> from scipy.cluster.hierarchy import ward, to_mlab_linkage
    >>> from scipy.spatial.distance import pdist

    >>> X = [[0, 0], [0, 1], [1, 0],
    ...      [0, 4], [0, 3], [1, 4],
    ...      [4, 0], [3, 0], [4, 1],
    ...      [4, 4], [3, 4], [4, 3]]

    >>> Z = ward(pdist(X))
    >>> Z
    array([[ 0.        ,  1.        ,  1.        ,  2.        ],
           [ 3.        ,  4.        ,  1.        ,  2.        ],
           [ 6.        ,  7.        ,  1.        ,  2.        ],
           [ 9.        , 10.        ,  1.        ,  2.        ],
           [ 2.        , 12.        ,  1.29099445,  3.        ],
           [ 5.        , 13.        ,  1.29099445,  3.        ],
           [ 8.        , 14.        ,  1.29099445,  3.        ],
           [11.        , 15.        ,  1.29099445,  3.        ],
           [16.        , 17.        ,  5.77350269,  6.        ],
           [18.        , 19.        ,  5.77350269,  6.        ],
           [20.        , 21.        ,  8.16496581, 12.        ]])

    After a linkage matrix ``Z`` has been created, we can use
    `scipy.cluster.hierarchy.to_mlab_linkage` to convert it
    into MATLAB format:

    >>> mZ = to_mlab_linkage(Z)
    >>> mZ
    array([[  1.        ,   2.        ,   1.        ],
           [  4.        ,   5.        ,   1.        ],
           [  7.        ,   8.        ,   1.        ],
           [ 10.        ,  11.        ,   1.        ],
           [  3.        ,  13.        ,   1.29099445],
           [  6.        ,  14.        ,   1.29099445],
           [  9.        ,  15.        ,   1.29099445],
           [ 12.        ,  16.        ,   1.29099445],
           [ 17.        ,  18.        ,   5.77350269],
           [ 19.        ,  20.        ,   5.77350269],
           [ 21.        ,  22.        ,   8.16496581]])

    The new linkage matrix ``mZ`` uses 1-indexing for all the
    clusters (instead of 0-indexing). Also, the last column of
    the original linkage matrix has been dropped.