"""
===============================
Visualize matrices with matshow
===============================

`~.axes.Axes.matshow` visualizes a 2D matrix or array as color-coded image.
"""
import matplotlib.pyplot as plt
import numpy as np

# a 2D array with linearly increasing values on the diagonal
a = np.diag(range(15))

plt.matshow(a)

plt.show()

# %%
#
# .. admonition:: References
#
#    The use of the following functions, methods, classes and modules is shown
#    in this example:
#
#    - `matplotlib.axes.Axes.imshow` / `matplotlib.pyplot.imshow`