from mpl_toolkits import mplot3d
import numpy as np
import matplotlib.pyplot as plt

#create 3d axes
fig = plt.figure()
ax = plt.axes(projection='3d')

#function for Z values
def f(x, y):
    c = [2, 3, 8, 3, 2, 8]
    a = [3, -5, 0, 3, -4, 6]
    b = [-4, -6, -1, 7, 0, 5]
    sum = 0
    for i in range(6):
        sum += c[i] / (1 + (x - a[i]) ** 2 + (y - b[i]) ** 2)
    return sum

# x and y values
x = np.linspace(-10, 10, 100)
y = np.linspace(-10, 10, 100)

X, Y = np.meshgrid(x, y)
Z = f(X, Y)

ax = plt.axes(projection ='3d')
ax.plot_surface(X, Y, Z, rstride=1, cstride=1,
                cmap='viridis')
ax.view_init(0, 90)
plt.show()