plot_utils.py 文件源码

def plot_ellipse(ax, mu, sigma, color="k"):
    """
    Based on
    http://stackoverflow.com/questions/17952171/not-sure-how-to-fit-data-with-a-gaussian-python.
    """

    # Compute eigenvalues and associated eigenvectors
    vals, vecs = np.linalg.eigh(sigma)

    # Compute "tilt" of ellipse using first eigenvector
    x, y = vecs[:, 0]
    theta = np.degrees(np.arctan2(y, x))

    # Eigenvalues give length of ellipse along each eigenvector
    w, h = 2 * np.sqrt(vals)

    ax.tick_params(axis='both', which='major', labelsize=20)
    ellipse = Ellipse(mu, w, h, theta, color=color)  # color="k")
    ellipse.set_clip_box(ax.bbox)
    ellipse.set_alpha(0.2)
    ax.add_artist(ellipse)