Overview of SAS/IML Software

SAS/IML software gives you access to a powerful and flexible programming language in a dynamic, interactive environment. The acronym IML stands for "interactive matrix language."

The fundamental object of the language is a data matrix. You can use SAS/IML software interactively (at the statement level) to see results immediately, or you can submit blocks of statements or an entire program. You can also encapsulate a series of statements by defining a module; you can call the module later to execute all of the statements in the module.

SAS/IML software is powerful. SAS/IML software enables you to concentrate on solving problems because necessary (but distracting) activities such as memory allocation and dimensioning of matrices are performed automatically. You can use built-in operators and call routines to perform complex tasks in numerical linear algebra such as matrix inversion or the computation of eigenvalues. You can define your own functions and subroutines by using SAS/IML modules. You can perform operations on a single value or take advantage of matrix operators to perform operations on an entire data matrix. For example, the following statement adds 1 to every element of the matrix x, regardless of the dimensions of x:

x = x+1;

The SAS/IML language contains statements that enable you to manage data. You can read, create, and update SAS data sets in SAS/IML software without using the DATA step. For example, the following statement reads a SAS data set to obtain phone numbers for all individuals whose last name begins with "Smith":

read all var{phone} where(lastname=:"Smith");

The result is phone, a vector of phone numbers.