Matrices

A matrix is a collection of numbers arranged in a two-dimensional (2-D) array structure. Each element of the matrix, call it

M

, occupies the

i

row and

j

column.

(8.1)

We say that

M

is an (

m

⊗

n

) matrix, which means that it has

m

rows and

n

columns. If

m = n

, we call the matrix square. If

m

= 1, the matrix is a row vector; and if

n

= 1, the matrix is a column vector.