utils.py 文件源码

def _plot_gaussian(mean, covariance, color, zorder=0):
    """Plots the mean and 2-std ellipse of a given Gaussian"""
    plt.plot(mean[0], mean[1], color[0] + ".", zorder=zorder)

    if covariance.ndim == 1:
        covariance = np.diag(covariance)

    radius = np.sqrt(5.991)
    eigvals, eigvecs = np.linalg.eig(covariance)
    axis = np.sqrt(eigvals) * radius
    slope = eigvecs[1][0] / eigvecs[1][1]
    angle = 180.0 * np.arctan(slope) / np.pi

    plt.axes().add_artist(pat.Ellipse(
        mean, 2 * axis[0], 2 * axis[1], angle=angle,
        fill=False, color=color, linewidth=1, zorder=zorder
    ))