# おのおのの銘柄の期待されるリターンを返す
mu = data.get_period_return_mean_vector() 
print(mu)

# 共分散行列Σのプロット
# 4つの銘柄の共分散行列を返す
sigma = data.get_period_return_covariance_matrix()
fig, ax = plt.subplots(1,1)
im = plt.imshow(sigma, extent=[-1,1,-1,1])
x_label_list = ['stock3', 'stock2', 'stock1', 'stock0']
y_label_list = ['stock3', 'stock2', 'stock1', 'stock0']
ax.set_xticks([-0.75,-0.25,0.25,0.75])
ax.set_yticks([0.75,0.25,-0.25,-0.75])
ax.set_xticklabels(x_label_list)
ax.set_yticklabels(y_label_list)
plt.colorbar()
plt.clim(-0.000002, 0.00001)
plt.show()