Animated Scatter Plot

Question

I would like to do an animation in python representing each point, dot by dot. I am doing it as I always have done it, but it does not work. Any help? I tried 2 different ways.

import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

%matplotlib nbagg

def mcd(a, b):
    resto = 0
    while(b > 0):
        resto = b
        b = a % b
        a = resto
    return a

N = 1200

n = list (range (N))
an = [1,1]

for i in range (2,N):
    k = i-1
    if mcd (n[i], an[k]) == 1:
        an.append (n[i] + 1 + an[k])
    else:
        an.append (an[k]/mcd (n[i], an[k]))

fig = plt.figure ()
ax = fig.add_subplot (111)
ax.grid (True)
ax.set_xlim(0, N*1.1)
pt, = ax.plot ([],[],'ko', markersize=2)

ax.plot (n,an, 'ko', markersize=2)

def init ():

    pt.set_data([],[])
    return (pt)

def animate (i,pt):

    pt.set_data (n[:i],an[:i])

    return (pt)

ani = FuncAnimation (fig, animate, fargs = (pt), frames=N, init_func=init, interval=50, blit = True)

plt.show ()

And the second way:

import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

%matplotlib nbagg

def mcd(a, b):
    resto = 0
    while(b > 0):
        resto = b
        b = a % b
        a = resto
    return a

N = 1200

n = list (range (N))
an = [1,1]

for i in range (2,N):
    k = i-1
    if mcd (n[i], an[k]) == 1:
        an.append (n[i] + 1 + an[k])
    else:
        an.append (an[k]/mcd (n[i], an[k]))

xdata, ydata = [],[]

fig = plt.figure ()
ax = fig.add_subplot(111)
ax.grid (True)
pt, = ax.plot ([],[],'ko', markersize=2)

ax.plot (n,an, 'ko', markersize=2)

def init ():
    ax.set_xlim(0, N*1.1)
    pt.set_data([],[])
    return (pt)

def animate (pt):
    xdata.append (n[i])
    ydata.append (an[i])

    pt.set_data (xdata,ydata)

    return (pt)

ani = FuncAnimation (fig, animate, fargs = (pt), frames=N, init_func=init, interval=50, blit = True)

plt.show ()

Using those codes, I get the entire figure with all the points. I would like to fill the graph point by point in an animated way.

Answer 1

The following will work

%matplotlib nbagg
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

def mcd(a, b):
    resto = 0
    while(b > 0):
        resto = b
        b = a % b
        a = resto
    return a

N = 1200

n = list (range (N))
an = [1,1]

for i in range (2,N):
    k = i-1
    if mcd (n[i], an[k]) == 1:
        an.append (n[i] + 1 + an[k])
    else:
        an.append (an[k]/mcd (n[i], an[k]))

fig = plt.figure ()
ax = fig.add_subplot (111)
ax.grid (True)
ax.set_xlim(0, N*1.1)
ax.set_ylim(min(an), max(an))
pt, = ax.plot([],[],'ko', markersize=2)

def init ():
    pt.set_data([], [])
    return pt,

def animate(i):
    pt.set_data (n[:i], an[:i])
    return pt,

ani = FuncAnimation (fig, animate, frames=N, init_func=init, interval=50, blit = True)

plt.show ()