%matplotlib inline
from matplotlib import pyplot as plt
import numpy as np
 
def f(x, y):
  return (1 - x / 2 + x ** 5 + y ** 3) * np.exp(-x ** 2 - y ** 2)
 
n = 10
x = np.linspace(-3, 3, 4 * n)
y = np.linspace(-3, 3, 3 * n)
X, Y = np.meshgrid(x, y)
plt.imshow(f(X, Y), cmap='hot', origin='low')
plt.colorbar(shrink=.83)
 
plt.xticks(())
plt.yticks(())

%matplotlib inline
from matplotlib import pyplot as plt
import numpy as np
 
ax = plt.subplot(1, 1, 1, polar=True)
#ax = plt.plot( polar=True)
N = 20
theta = np.arange(0.0, 2 * np.pi, 2 * np.pi / N)
radii = 10 * np.random.rand(N)
width = np.pi / 4 * np.random.rand(N)
bars = plt.bar(theta, radii, width=width, bottom=0.0)
 
for r,bar in zip(radii, bars):
  bar.set_facecolor(plt.cm.jet(r/10.))
  bar.set_alpha(0.5)
 
ax.set_xticklabels([])
ax.set_yticklabels([])