Matrices

(25th-April-2021)

Matrices

: A matrix is a 2-D array of numbers, so each element is identified by two indices instead of just one. We usually give matrices upper-case variable names with bold typeface, such as A . If a real-valued matrix A has a height of m and a width of n, then we say that A ∈ R m×n. We usually identify the elements of a matrix using its name in italic but not bold font, and the indices are listed with separating commas.

For example, A 1,1 is the upper left entry of A and A m,n is the bottom right entry. We can identify all of the numbers with vertical coordinate i by writing a “:” for the horizontal coordinate.