Module « scipy.spatial.distance »

Fonction sokalsneath - module scipy.spatial.distance

Signature de la fonction sokalsneath

def sokalsneath(u, v, w=None) 

Description

sokalsneath.__doc__

    Compute the Sokal-Sneath dissimilarity between two boolean 1-D arrays.

    The Sokal-Sneath dissimilarity between `u` and `v`,

    .. math::

       \frac{R}
            {c_{TT} + R}

    where :math:`c_{ij}` is the number of occurrences of
    :math:`\mathtt{u[k]} = i` and :math:`\mathtt{v[k]} = j` for
    :math:`k < n` and :math:`R = 2(c_{TF} + c_{FT})`.

    Parameters
    ----------
    u : (N,) array_like, bool
        Input array.
    v : (N,) array_like, bool
        Input array.
    w : (N,) array_like, optional
        The weights for each value in `u` and `v`. Default is None,
        which gives each value a weight of 1.0

    Returns
    -------
    sokalsneath : double
        The Sokal-Sneath dissimilarity between vectors `u` and `v`.

    Examples
    --------
    >>> from scipy.spatial import distance
    >>> distance.sokalsneath([1, 0, 0], [0, 1, 0])
    1.0
    >>> distance.sokalsneath([1, 0, 0], [1, 1, 0])
    0.66666666666666663
    >>> distance.sokalsneath([1, 0, 0], [2, 1, 0])
    0.0
    >>> distance.sokalsneath([1, 0, 0], [3, 1, 0])
    -2.0