odebook.py 文件源码

def normvectorfield(xs,ys,fs,**kw):
    """
    plot normalized vector field

    kwargs
    ======

    - length is a desired length of the lines (default: 1)
    - the rest of kwards are passed to plot
    """
    length = kw.pop('length') if 'length' in kw else 1
    x, y = np.meshgrid(xs, ys)
    # calculate vector field
    vx,vy = fs(x,y)
    # plot vecor field
    norm = length /np.sqrt(vx**2+vy**2)
    plt.quiver(x, y, vx * norm, vy * norm, angles='xy',**kw)