Book Image

NumPy Beginner's Guide - Second Edition

By : Ivan Idris
Book Image

NumPy Beginner's Guide - Second Edition

By: Ivan Idris

Overview of this book

NumPy is an extension to, and the fundamental package for scientific computing with Python. In today's world of science and technology, it is all about speed and flexibility. When it comes to scientific computing, NumPy is on the top of the list. NumPy Beginner's Guide will teach you about NumPy, a leading scientific computing library. NumPy replaces a lot of the functionality of Matlab and Mathematica, but in contrast to those products, is free and open source. Write readable, efficient, and fast code, which is as close to the language of mathematics as is currently possible with the cutting edge open source NumPy software library. Learn all the ins and outs of NumPy that requires you to know basic Python only. Save thousands of dollars on expensive software, while keeping all the flexibility and power of your favourite programming language.You will learn about installing and using NumPy and related concepts. At the end of the book we will explore some related scientific computing projects. This book will give you a solid foundation in NumPy arrays and universal functions. Through examples, you will also learn about plotting with Matplotlib and the related SciPy project. NumPy Beginner's Guide will help you be productive with NumPy and have you writing clean and fast code in no time at all.
Table of Contents (19 chapters)
Numpy Beginner's Guide Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Time for action – simulating life


The following code is an implementation of Game of Life with some modifications, as follows:

  • Clicking once with the mouse draws a cross until we click again

  • Pressing the r key resets the grid to a random state

  • Pressing b creates blocks based on the mouse position

  • Pressing g creates gliders

The most important data structure in the code is a two-dimensional array holding the color values of the pixels on the game screen. This array is initialized with random values and then recalculated for each iteration of the game loop. More information about the involved functions can be found in the next section.

  1. To evaluate the rules, we will use convolution, as follows.

    def get_pixar(arr, weights):
      states = ndimage.convolve(arr, weights, mode='wrap')
    
      bools = (states == 13) | (states == 12 ) | (states == 3)
    
      return bools.astype(int)
  2. We can draw a cross using basic indexing tricks that we learned in Chapter 2, Beginning with NumPy Fundamentals.

    def draw_cross(pixar):
     ...