CHAPTER 6 - Matrices of Numbers and Arrays of Strings

Abstract

This chapter highlights matrix operations, different character strings, and facilities for handling them. A matrix is a 2D array. Elements may be referenced in the conventional way with two subscripts. Alternatively, one subscript may be used, in which case the matrix is “unwound” by columns. Arrays may have more than two dimensions. In the case of a 3D array, the third subscript may be thought of as numbering pages, with each page containing a matrix defined by the first two subscripts. For this chapter the term “matrix” has two distinct meanings: an arrangement of data in rows and columns; and a mathematical object for which particular mathematical operations are defined. Further matrix multiplication is probably the most important matrix operation. It is used widely in such areas as network theory linear systems of equations, transformation of coordinate systems, and population modeling to name but a few.