额外窗口 jupyter 笔记本 matplotlib 动画

Question

I've found another thread on this site with the same problem that I have. But the solutions of that thread do not help me for some reason. The problem is this, I have this code:

from matplotlib.animation import FuncAnimation
from IPython.display import HTML
a_lijst = np.arange(-1,2,0.1)
fig, ax = plt.subplots()
x = np.arange(-1,1,0.01)

def verandering(X,V,a):
    #u -> X'
    #v -> Y'
    u = V
    v = -X - (a*V**3 - V)
    return [u,v]

def euler(initx,inity,a,stapgrootte,periode):
    #initiële condities
    X = initx
    V = inity
    x = []
    y = []
    for i in range(0,periode):
        x.append(X)
        y.append(V)
        X += stapgrootte*verandering(x[-1],y[-1],a)[0]
        V += stapgrootte*verandering(x[-1],y[-1],a)[1]
    return x,y

def init():
    plt.xlabel('x')
    plt.ylabel('y')
    plt.xlim(-1,1)
    plt.ylim(-2,2)
    
# animation function. This is called sequentially
def animate(i):
    ax.clear()
    ax.set_ylim(-1,1)
    ax.set_xlim(-2,2)
    for coordinaat in coordinaten:
        x_i = coordinaat[0]
        y_i = coordinaat[1]
        x,y = euler(x_i,y_i,a_lijst[i],0.1,100)
        ax.plot(x,y)
    ax.set_title('a={}'.format(a_lijst[i]))
# call the animator. blit=True means only re-draw the parts that have changed.
anim = FuncAnimation(fig, animate, init_func=init,
                               frames=30, interval=100)
plt.close()
HTML(anim.to_jshtml())

now, just as in the previous thread, there are 2 plots created but even with the plt.close() and putting HTML(anim.to_jshtml()) in a different cell, and using %%capture on the other cell, I still get 2 plots after executing the HTML(anim.to_jshtml()) code. What am I doing wrong?

Answer 1

I found out that the extra window disappears when I remove the init function (of course also from FuncAnimation) and thus just have the animate function. (This is because of the animate function not having to use the init function, and thus also works when using ax instead of plt in the init function)