SAS/IML(R) 9.2 User's Guide

Product	Release
SAS/IML	9.2

Introduction to SAS/IML Software

SAS/IML Software: Highlights

SAS/IML software is a programming language.

You can program easily and efficiently with the many features for arithmetic and character expressions in SAS/IML software. You have access to a wide range of built-in subroutines designed to make your programming fast, easy, and efficient. Because SAS/IML software is part of the SAS System, you can access SAS data sets or external files with an extensive set of data processing commands for data input and output, and you can edit existing SAS data sets or create new ones.

SAS/IML software has a complete set of control statements, such as DO/END, START/FINISH, iterative DO, IF-THEN/ELSE, GOTO, LINK, PAUSE, and STOP, giving you all of the commands necessary for execution control and program modularization. See the "Control Statements" section for details.

SAS/IML software operates on matrices.

While most programming languages deal with single data elements, the fundamental data element in SAS/IML software is the matrix, a two-dimensional (row

column) array of numeric or character values.

SAS/IML software possesses a powerful vocabulary of operators.

You can access built-in matrix operations that require calls to math-library subroutines in other languages. You have access to many operators, functions, and CALL subroutines.

SAS/IML software uses operators that apply to entire matrices.

You can add elements of the matrices

and

with the expression

. You can perform matrix multiplication with the expression

and perform elementwise multiplication with the expression $a\char93 b$ .

SAS/IML software is interactive.

You can execute a command as soon as you enter it, or you can collect commands in a module to execute later. When you execute a command, you see the results immediately. You can interact with an executing module by programming SAS/IML software to pause, enabling you to enter additional statements before continuing execution.

SAS/IML software is dynamic.

You do not need to declare, dimension, and allocate storage for a data matrix. SAS/IML software does this automatically. You can change the dimension or type of a matrix at any time. You can open multiple files or access many libraries. You can reset options or replace modules at any time.

SAS/IML software processes data.

You can read all observations or read conditionally selected observations from a SAS data set into a matrix, creating either multiple vectors (one for each variable in the data set) or a matrix that contains a column for each data set variable. You can create a new SAS data set, or you can edit or append observations to an existing SAS data set.

SAS/IML software produces graphics.

You have access to a wide range of graphics commands, enabling you to visually explore relationships in data.

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