rplot.py 文件源码

def work(self, fig=None, ax=None):
        """Draw a two dimensional kernel density plot.
        You can specify either a figure or an axis to draw on.

        Parameters:
        -----------
        fig: matplotlib figure object
        ax: matplotlib axis object to draw on

        Returns:
        --------
        fig, ax: matplotlib figure and axis objects
        """
        if ax is None:
            if fig is None:
                return fig, ax
            else:
                ax = fig.gca()
        x = self.data[self.aes['x']]
        y = self.data[self.aes['y']]

        # TODO: unused?
        # rvs = np.array([x, y])

        x_min = x.min()
        x_max = x.max()
        y_min = y.min()
        y_max = y.max()
        X, Y = np.mgrid[x_min:x_max:200j, y_min:y_max:200j]
        positions = np.vstack([X.ravel(), Y.ravel()])
        values = np.vstack([x, y])
        import scipy.stats as stats
        kernel = stats.gaussian_kde(values)
        Z = np.reshape(kernel(positions).T, X.shape)
        ax.contour(Z, extent=[x_min, x_max, y_min, y_max])
        return fig, ax