Book Image

GNU Octave Beginner's Guide

By : Jesper Schmidt Hansen
Book Image

GNU Octave Beginner's Guide

By: Jesper Schmidt Hansen

Overview of this book

Today, scientific computing and data analysis play an integral part in most scientific disciplines ranging from mathematics and biology to imaging processing and finance. With GNU Octave you have a highly flexible tool that can solve a vast number of such different problems as complex statistical analysis and dynamical system studies.The GNU Octave Beginner's Guide gives you an introduction that enables you to solve and analyze complicated numerical problems. The book is based on numerous concrete examples and at the end of each chapter you will find exercises to test your knowledge. It's easy to learn GNU Octave, with the GNU Octave Beginner's Guide to hand.Using real-world examples the GNU Octave Beginner's Guide will take you through the most important aspects of GNU Octave. This practical guide takes you from the basics where you are introduced to the interpreter to a more advanced level where you will learn how to build your own specialized and highly optimized GNU Octave toolbox package. The book starts by introducing you to work variables like vectors and matrices, demonstrating how to perform simple arithmetic operations on these objects before explaining how to use some of the simple functionality that comes with GNU Octave, including plotting. It then goes on to show you how to write new functionality into GNU Octave and how to make a toolbox package to solve your specific problem. Finally, it demonstrates how to optimize your code and link GNU Octave with C and C++ code enabling you to solve even the most computationally demanding tasks. After reading GNU Octave Beginner's Guide you will be able to use and tailor GNU Octave to solve most numerical problems and perform complicated data analysis with ease.
Table of Contents (15 chapters)
GNU Octave
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface

Chapter 5. Extensions: Write Your Own Octave Functions

In this chapter, you will learn how to write your own Octave functions. This will not only enable you to utilize more of Octave's built-in functionality, it also makes it possible to extend Octave to do pretty much anything you want it to in a highly reusable and modular manner.

After reading this chapter, you will be able to:

  • Write your own Octave functions.

  • Check and validate user inputs to the functions.

  • Write function help text.

  • Define mathematical functions that can be used by Octave to solve different numerical problems.

  • Perform simple debugging of your functions.

  • Vectorize your code.

Your first Octave function

In general, the syntax for a function is:

function [output1, output2, ...] = functionname(input1,input2,...)
do something (body)
endfunction

where output1, output2, ... are the output variables generated by the function and input1, input2, ... are inputs to the function and are also referred to as input arguments. The function...