The DO Loop
Statistical programming in SAS with an emphasis on SAS/IML programs
The other day I was doing some computations that caused me to wonder, "What is the smallest power of 2 that is greater than a given number?" The mathematics is straightforward. Given a number n, find the least value of k such that 2k ≥ n or, equivalently, k ≥
SAS/IML 13.1 includes a handy function for programmers who write a lot of modules. The PARENTNAME function obtains the name of the symbol that was passed in as a parameter to a user-defined module. How is this useful? Well, suppose that you want to create a SAS/IML module that prints
When you create a histogram with statistical software, the software uses the data (including the sample size) to automatically choose the width and location of the histogram bins. The resulting histogram is an attempt to balance statistical considerations, such as estimating the underlying density, and "human considerations," such as choosing
A SAS customer wrote, "I have access to PROC IML through SAS OnDemand for Academics. What is the best way for me to learn to program in the SAS/IML language? How do I get started with PROC IML?" That is an excellent question, and I'm happy to offer some suggestions.
Unless you diligently read the "What's New" chapter for each release of SAS software, it is easy to miss new features that appear in the language. People who have been writing SAS/IML programs for decades are sometimes surprised when I tell them about a useful new function or programming feature.
In a previous blog post, I described how to generate combinations in SAS by using the ALLCOMB function in SAS/IML software. The ALLCOMB function in Base SAS is the equivalent function for DATA step programmers. Recall that a combination is a unique arrangement of k elements chosen from a set