How can I plot many thousands of circles quickly?

Question

I\'m trying to plot several (many thousands) of circle objects - I don\'t have much experience working with python. I\'m interested in specifying the position, radius and color

Answer 1

You would certainly want to move ...gca() outside of your loop. You can also use list comprehension.

fig = plt.figure()
ax = plt.gcf().gca()

[ax.add_artist(plt.Circle((xvals[q],yvals[q]),rvals[q],color=[0,0,0])) 
 for q in xrange(4)]  # range(4) for Python3

Below are some tests to generate 4,000 circles using the various methods:

xvals = [0,.1,.2,.3] * 1000
yvals = [0,.1,.2,.3] * 1000
rvals = [0,.1,.1,.1] * 1000

%%timeit -n5 fig = plt.figure(); ax = plt.gcf().gca()
for q in range(4000):
    circle1=plt.Circle((xvals[q], yvals[q]), rvals[q], color=[0,0,0])
    plt.gcf().gca().add_artist(circle1)
5 loops, best of 3: 792 ms per loop

%%timeit -n5 fig = plt.figure(); ax = plt.gcf().gca()
for q in xrange(4000):
    ax.add_artist(plt.Circle((xvals[q],yvals[q]),rvals[q],color=[0,0,0]))
5 loops, best of 3: 779 ms per loop

%%timeit -n5 fig = plt.figure(); ax = plt.gcf().gca()
[ax.add_artist(plt.Circle((xvals[q],yvals[q]),rvals[q],color=[0,0,0])) for q in xrange(4000)]
5 loops, best of 3: 730 ms per loop