Rick Wicklin
Rick Wicklin RSS
Research Statistician Developer

Rick Wicklin, PhD, is a distinguished researcher in computational statistics at SAS and is a principal developer of PROC IML and SAS/IML Studio. His areas of expertise include computational statistics, statistical graphics, and modern methods in statistical data analysis. Rick is author of the books Statistical Programming with SAS/IML Software and Simulating Data with SAS. Follow @RickWicklin on Twitter.

Recent Posts

Create a custom PDF and CDF in SAS

In my previous post, I showed how to approximate a cumulative density function (CDF) by evaluating only the probability density function. The technique uses the ... Read More

An easy way to approximate a cumulative distribution function

Evaluating a cumulative distribution function (CDF) can be an expensive operation. Each time you evaluate the CDF for a continuous probability distribution, the software has ... Read More

Avoid loops, avoid the APPLY function, vectorize!

Last week I received a message from SAS Technical Support saying that a customer's IML program was running slowly. Could I look at it to ... Read More

Plotting multiple time series in SAS/IML (Wide to Long, Part 2)

I recently wrote about how to overlay multiple curves on a single graph by reshaping wide data (with many variables) into long data (with a ... Read More

Plotting multiple series: Transforming data from wide to long

Data. To a statistician, data are the observed values. To a SAS programmer, analyzing data requires knowledge of the values and how the data are ... Read More

Complete cases: How to perform listwise deletion in SAS

SAS procedures usually handle missing values automatically. Univariate procedures such as PROC MEANS automatically delete missing values when computing basic descriptive statistics. Many multivariate procedures ... Read More

Monitor the progress of a long-running SAS/IML program

When you have a long-running SAS/IML program, it is sometimes useful to be able to monitor the progress of the program. For example, suppose you ... Read More

Friends don't let friends concatenate results inside a loop

Friends have to look out for each other. Sometimes this can be slightly embarrassing. At lunch you might need to tell a friend that he ... Read More

Binary heart in SAS

The xkcd comic often makes me think and laugh. The comic features physics, math, and statistics among its topics. Many years ago, the comic showed ... Read More

Creating an array of matrices

The SAS DATA step supports multidimensional arrays. However, matrices in SAS/IML are like mathematical matrices: they are always two dimensional. In simulation studies you might ... Read More