Page 15 - Computational Colour Science Using MATLAB

2 INTRODUCTION

1.2 Why base this book upon MATLAB?

This book describes algorithms and mathematical procedures in colour science
and illustrates these procedures using the numerical software tool called
MATLAB. MATLAB provides several features that make it suitable for the
implementation of algorithms in general, and colour-science algorithms in
particular, and results in code that is easily understandable by the reader with
relatively little experience of writing software. These features include the use of
operations upon vectors and matrices to enable compact code that avoids the
excessive use of looping procedures, the provision of a massive library of
functions that the MATLAB programmer can call upon and the ease of use of
graphics functions to enable the user to easily and effectively visualise complex
data structures.
Most computer languages are very dependent upon a variety of ‘looping’
procedures to execute summations or to implement iterative techniques whereas
MATLAB enables these types of operations to be performed with a fraction of
the code. For example, if we have two variables x and y, each consisting of five
entries, and we wish to compute the product of the corresponding entries and
then sum the results to yield a single number, we might write code that in BASIC
looks like the following:

sum = 0
FOR i=1 TO 5
sum = sum + x(i)*y(i)
NEXT i

In MATLAB the four lines of BASIC code shown could be replaced by the single
line

sum = x*y;

Expressed in terms of linear algebra MATLAB will perform the inner product of
the vectors x and y automatically. In the MATLAB environment it is not
necessary to specify how many entries the variables contain, so long as the
dimensions of these variables define a valid matrix operation. A variable in
MATLAB can represent a single number, a vector or a whole matrix. The
operation given, for example, by

y = 2*x

will assign to y twice the value of x if x defines a single number, but twice the
value of every element in x if x is a vector or a matrix. The compact nature of
MATLAB code allows complex and sophisticated algorithms to be explained