transfer_functions.py 文件源码

def add_gaussian(self, location, width, height):
        r"""Add a Gaussian distribution to the transfer function.

        Typically, when rendering isocontours, a Gaussian distribution is the
        easiest way to draw out features.  The spread provides a softness.
        The values are calculated as :math:`f(x) = h \exp{-(x-x_0)^2 / w}`.

        Parameters
        ----------
        location : float
            The centroid of the Gaussian (:math:`x_0` in the above equation.)
        width : float
            The relative width (:math:`w` in the above equation.)
        height : float
            The peak height (:math:`h` in the above equation.)  Note that while
            values greater 1.0 will be accepted, the values of the transmission
            function are clipped at 1.0.

        Examples
        --------

        >>> tf = TransferFunction( (-10.0, -5.0) )
        >>> tf.add_gaussian(-9.0, 0.01, 1.0)
        """
        vals = height * np.exp(-(self.x - location)**2.0/width)
        self.y = np.clip(np.maximum(vals, self.y), 0.0, np.inf)
        self.features.append(('gaussian', "location(x):%3.2g" % location, 
                              "width(x):%3.2g" % width, "height(y):%3.2g" % height))