Matrices are useful for representing data and are very efficient for working with data.
For example, suppose you measured the daily high temperatures in September for six different cities and want to convert the readings from Fahrenheit to Celsius. These statements direct the flow of execution of IML statements, and enable program modularization. IML automatically loads, resolves, and executes a module when you use it. A powerful set of commands, called graphics primitives, are provided to create customized displays. A set of attributes such as color and linestyle can be associated with each primitive.