three_peaks.py

import numpy as np
from scipy import stats

n = 100

r = 10
x = np.linspace(-1.8, 1.8, n)
y = np.linspace(-1.8, 1.8, n)
X, Y = np.meshgrid(x, y)


XY = np.empty((n * n, 2))
XY[:, 0] = X.flatten()
XY[:, 1] = Y.flatten()

cov = np.eye(2) * 0.2
dist = stats.multivariate_normal(np.array([-0.6, -0.6]), cov)
Z = dist.pdf(XY).reshape((n, n))

cov = np.eye(2) * 0.2
dist = stats.multivariate_normal(np.array([0.6, 0.6]), cov)
Z += dist.pdf(XY).reshape((n, n))

cov = np.array([[0.1, 0.002],
               [0.005, 0.1]])
dist = stats.multivariate_normal(np.array([0.5, -0.5]), cov)
Z += dist.pdf(XY).reshape((n, n)) * 1

cov = np.array([[0.05, 0.002],
               [0.003, 0.05]])
dist = stats.multivariate_normal(np.array([-0.5, -1.0]), cov)
Z += dist.pdf(XY).reshape((n, n)) * 0.15