# This program will make plots in python, version 3+, using
# utilities from matplotlib and numpy.  This program investigates
# the use of the `rc' module of matplotlib.pyplot to change
# line widths and font sizes.  It also does examples to make
# use of LaTeX math symbols in text.

# Always include these next two import commands.

import numpy as np
import matplotlib.pyplot as plt

# ***** Make a plot with axis labels & in picture text. *****

x1 = np.arange(1, 19, .4)
y1a = np.log10(x1)
y1b = 0.01 * x1**2
y1c = 0.9 * np.sin(x1)

plt.plot(x1, y1a, 'r-')
plt.xlabel('X Data', labelpad=10)
plt.ylabel('Log(X)', labelpad=10)
plt.title('The Common Log Function')
plt.text(2.0, 1.2, 'This is an in-picture text.')

plt.show()

# This plot reproduces the plot above, but rotates the in
# picture text by 30 degrees.

plt.plot(x1, y1a, 'r-')
plt.xlabel('X Data', labelpad=10)
plt.ylabel('Log(X)', labelpad=10)
plt.title('The Common Log Function')
plt.text(2.0, 1.2, 'This is an in-picture text.', rotation=30)

plt.show()

# Now reproduce the first plot, but make the lines thicker
# (both the plot and axes) and font bigger of all of the
# text.

plt.rc('lines', linewidth=2)
plt.rc('font', size=16)
plt.rc('axes', linewidth=2)

plt.plot(x1, y1a, 'r-')
plt.xlabel('X Data', labelpad=10)
plt.ylabel('Log(X)', labelpad=10)
plt.title('The Common Log Function')
plt.text(2.0, 1.2, 'This is an in-picture text.')

plt.show()

# We will now include some LaTeX math commands in the
# various text captions.

plt.plot(x1, y1c, 'bo-')
plt.xlabel(r'Angle $\theta$')
plt.ylabel(r'sin $\theta$')
plt.title('The Sine Function')

plt.show()