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

Time for action - using whos


We are working with quite a few variables now. We can list them all with whos:

octave:48>whos
Variables in the current scope:

Attr

Name

Size

Bytes

 

Class

====

====

====

=====

 

=====

 

A

2x2

32

 

double

 

B

2x2x2

128

 

double

 

T

2x6

12

 

char

 

Z

2x2

64

 

double

 

a

1x1

8

 

double

 

ans

1x9

9

 

char

 

b

1x5

40

 

double

 

c

3x1

24

 

double

 

d

1x12

96

 

double

 

projectile

1x3

42

 

cell

 

projectiles

2x3

83

 

cell

 

s

1x2

83

 

struct

 

t

1x11

11

 

char

 

z

1x1

16

 

double

Total is 81 elements using 648 bytes

What just happened?

As seen above, whos prints out five columns. The first column can have values g or p, which means that the variable is global or persistent. We shall return to what these qualifiers mean in Chapter 5. In our case, all the variables are what are named local, which is not stated explicitly by the command whos. A local variable is characterized by being visible and therefore accessible to a given workspace...