CODEWITHSUNDEEP
pythonanimationmatplotlibplot
JavaCoder
JavaCoder

Reputation: 11

Can't get my program to animate circles in 2D in matplotlib

I am trying to animate n circles in 2D with matplotlib, but when run, my code only shows one circle, stationary, regardless of what I make n. Does anyone know how to fix it, and what is wrong with it?

%matplotlib notebook
import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation

fig=plt.figure()
ax = plt.axes(xlim=(0, 40), ylim=(0, 40))

number_of_particles = int(input("How many particles would you like?"))
data = np.zeros((1000,number_of_particles))
dict_of_circles = {}
for n in range(number_of_particles):
    data[:,n] = [20*(1+np.sin(float(x)/50*n+50)) for x in range(1000)]
    dict_of_circles["circle"+str(n+1)] = plt.Circle((data[0,n],1.0),0.5,fc='b')


def init():
    for n in range(number_of_particles):
        dict_of_circles["circle"+str(n+1)].center = (data[0,n],1)
        ax.add_patch(dict_of_circles["circle"+str(n+1)])
        return dict_of_circles["circle"+str(n+1)]

def animate(i):
    for n in range(number_of_particles):
        dict_of_circles["circle"+str(n+1)].center = (data[i,n],1)
        return dict_of_circles["circle"+str(n+1)]

anim=animation.FuncAnimation(fig,animate,init_func=init,frames=1000,blit=True)

plt.show()

Upvotes: 0

Views: 1310

Answers (1)

ImportanceOfBeingErnest
ImportanceOfBeingErnest

Reputation: 339610

Two problems:

  1. The indentation is wrong. You need to return from the function not from within the loop.
  2. You need to return an iterable of artists, not a single artist, because you want all artists to update.

Complete code:

import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation

fig=plt.figure()
ax = plt.axes(xlim=(0, 40), ylim=(0, 40))

number_of_particles = 10
data = np.zeros((1000,number_of_particles))
dict_of_circles = {}
for n in range(number_of_particles):
    data[:,n] = [20*(1+np.sin(float(x)/50*n+50)) for x in range(1000)]
    dict_of_circles["circle"+str(n+1)] = plt.Circle((data[0,n],1.0),0.5,fc='b')


def init():
    for n in range(number_of_particles):
        dict_of_circles["circle"+str(n+1)].center = (data[0,n],1)
        ax.add_patch(dict_of_circles["circle"+str(n+1)])
    return dict_of_circles.values()

def animate(i):
    for n in range(number_of_particles):
        dict_of_circles["circle"+str(n+1)].center = (data[i,n],1)
    return dict_of_circles.values()

anim=animation.FuncAnimation(fig,animate,init_func=init,frames=1000,blit=True)

plt.show()

Upvotes: 1

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