Book Image

NumPy: Beginner's Guide

By : Ivan Idris
Book Image

NumPy: Beginner's Guide

By: Ivan Idris

Overview of this book

Table of Contents (21 chapters)
NumPy Beginner's Guide Third Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
NumPy Functions' References
Index

Time for action – plotting the sinc function


We will plot the sinc() function:

  1. Compute evenly spaced values with the NumPy linspace() function:

    x = np.linspace(0, 4, 100)
  2. Call the NumPy sinc() function:

    vals = np.sinc(x)
  3. Plot the sinc() function with matplotlib:

    plt.plot(x, vals)
    plt.show()

    The sinc() function will have the following output:

    The sinc2d() function requires a two-dimensional array. We can create it with the outer() function, resulting in this plot (code is in the following section):

What just happened?

We plotted the well-known sinc function with the NumPy sinc() function (see plot_sinc.py):

import numpy as np
import matplotlib.pyplot as plt


x = np.linspace(0, 4, 100)
vals = np.sinc(x)

plt.plot(x, vals)
plt.title('Sinc function')
plt.xlabel('x')
plt.ylabel('y')
plt.grid()
plt.show()

We did the same for two dimensions (see sinc2d.py):

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 4, 100)
xx = np.outer(x, x)
vals = np.sinc(xx)

plt.imshow(vals)
plt.title('Sinc...