What's New in SAS/IML 9.2

New Features

New to SAS/IML are the following:

• a set of new modules for sampling from multivariate distributions
• a set of general performance improvements
• a new call to interface with ODS Statistical Graphics
• a new function to compute B-splines
• a new programming syntax to specify vector-matrix operations
• a set of new functions to compute the geometric and harmonic means

Modules for Multivariate Random Sampling

New modules have been added to the IMLMLIB library. These modules generate random samples of observations from multivariate distributions in variables. See the Module Library documentation for details.

The modules and associated multivariate distributions are as follows:

RANDDIRICHLET

generates a random sample from a Dirichlet distribution (a multivariate generalization of the beta distribution).

RANDMULTINOMIAL

generates a random sample from a multinomial distribution (a multivariate generalization of the binomial distribution)

RANDMVT

generates a random sample from a multivariate Student's distribution.

RANDNORMAL

generates a random sample from a multivariate normal distribution.

RANDWISHART

generates a random sample from a Wishart distribution (a multivariate generalization of the gamma distribution).

Performance Improvements

Several optimization methods have been implemented to speed up basic matrix operations and improve the efficiency of memory management in SAS/IML. These changes result in faster-running SAS/IML programs.

ODS Statistical Graphics Interface

A new ODSGRAPH call has been introduced that enables you to render graphs created with the new graphics commands that have been added to PROC TEMPLATE. This addition is designed to make it easier for you to create standard graphs and save them in a format of your choice. See the Language Reference chapter for full details about this new call.

BSPLINE Function

A new BSPLINE function has been introduced that computes a B-spline basis for a given numeric input vector, degree, and knot specification. See the Language Reference chapter for a full description of the function and its inputs.

Vector-Matrix Operations

SAS/IML elementwise operations now permit you to specify conforming vector-matrix operations. For example, if is a 1 by row vector, and is an by matrix, then the expression + evaluates to the addition of to each row of . This change was introduced to reduce the need for explicit loops and increase the efficiency of this type of calculation. See the Language Reference chapter for full details of this change.

GEOMEAN and HARMEAN Functions

Two new functions have been added to compute the geometric mean and the harmonic mean of a matrix of positive numbers. See the Language Reference chapter for full details.

New Related Software

SAS/STAT users will be interested in SAS® Stat Studio, which is new software for data exploration and analysis. It provides a highly flexible programming environment in which you can run SAS/STAT or SAS/IML® analyses and display the results with dynamically linked graphics and data tables. Stat Studio is intended for data analysts who write SAS programs to solve statistical problems but need more versatility for data exploration and model building. The programming language in Stat Studio, which is called IMLPlus, is an enhanced version of the IML programming language. IMLPlus extends IML to provide new language features, including the ability to create and manipulate statistical graphics, call SAS procedures as functions, and call computational programs written in C, C++, Java, and Fortran. Stat Studio runs on a PC in the Microsoft Windows operating environment.

Stat Studio is also the successor to the SAS/INSIGHT® product and provides the same interactive functionality. It is distributed with the SAS/IML product. For more information about Stat Studio, see the Stat Studio 3.1: User's Guide and Stat Studio 3.1 for SAS/STAT Users.