The DO Loop
Statistical programming in SAS with an emphasis on SAS/IML programs
Each year my siblings choose names for a Christmas gift exchange. It is not unusual for a sibling to pick her own name, whereupon the name is replaced into the hat and a new name is drawn. In fact, that "glitch" in the drawing process was a motivation for me
If you write an n x p matrix from PROC IML to a SAS data set, you'll get a data set with n rows and p columns. For some applications, it is more convenient to write the matrix in a "long format" with np observations and three columns. The first
For several years, there has been interest in calling R from SAS software, primarily because of the large number of special-purpose R packages. The ability to call R from SAS has been available in SAS/IML since 2009. Previous blog posts about R include a video on how to call R
When I call R from within the SAS/IML language, I often pass parameters from SAS into R. This feature enables me to write general-purpose, reusable, modules that can analyze data from many different data sets. I've previously blogged about how to pass values to SAS procedures from PROC IML by
In using a vector-matrix language such as SAS/IML, MATLAB, or R, one of the challenges for programmers is learning how to vectorize computations. Often it is not intuitive how to program a computation so that you avoid looping over the rows and columns of a matrix. However, there are a
My daughter's middle school math class recently reviewed how to compute the greatest common factor (GCF) and the least common multiple (LCM) of a set of integers. (The GCF is sometimes called the greatest common divisor, or GCD.) Both algorithms require factoring integers into a product of primes. While helping