Book Image

Sage Beginner's Guide

By : Craig Finch
1 (1)
Book Image

Sage Beginner's Guide

1 (1)
By: Craig Finch

Overview of this book

Table of Contents (17 chapters)
Sage Beginner's Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Time for action – putting it all together


Let's produce a simple document with LaTeX that incorporates typeset equations and graphics. This is a suitable starting point for a report, journal article, or homework assignment. First, let's make a plot of the Bessel function of the first kind for three values of n.

from matplotlib import pyplot as plt
import numpy

def J_n_numerical(n, x):
    integrand(n1, x1, t) = cos(n1 * t - x1 * sin(t))
    J_n = numpy.zeros(len(x))
    for j in range(len(x)):
        J_n[j] = 1 / pi.n() * integrand(n1=n, x1=x[j]).nintegrate(t, 0, pi)[0]
    return J_n

n_values = [0, 1, 2]
x = numpy.arange(0.0, 10.0, 0.1)

plt.figure()
for n in n_values:
    plt.plot(x, J_n_numerical(n, x), label='n=' + str(n))
plt.xlabel('x')
plt.ylabel('J(x)')
plt.legend(loc='upper right')
plt.savefig('J_n.pdf')
plt.close()

The plot will be saved as a PDF file in the SAGE_TEMP directory, so you won't see the plot in your browser. Instead, you will see a link to the file. Click this link...