Blog Archives

Mathematical art (part 2): Unweaving matrices

September 4, 2015
By
Mathematical art (part 2): Unweaving matrices

In my previous blog post, I showed how you can use SAS to program a "weaving" algorithm that takes an image, cuts it into strips, and weaves the strips together to create mathematical art. I used matrices and heat maps for the computations and visualization. At the end of the […] The post Mathematical art (part 2): Unweaving matrices appeared first on The DO Loop.

Read more »

Mathematical art: Weaving matrices

September 2, 2015
By
Mathematical art: Weaving matrices

An artist friend of mine recently created a beautiful abstract image and described the process on her blog. She says that "after painting my initial square, I cut it into strips and split them down the middle, then wove them together.... I had no idea when I started piecing these […] The post Mathematical art: Weaving matrices appeared first on The DO Loop.

Read more »

Compute the number of digits in an integer

August 31, 2015
By
Compute the number of digits in an integer

The title of this blog post might seem strange, but I occasionally need to compute the number of digits in a number, usually because I am trying to stuff an integer value into a string. Each time, I have to derive the formula from scratch, so I am writing this […] The post Compute the number of digits in an integer appeared first on The DO Loop.

Read more »

Monitor convergence during simulation studies in SAS

August 26, 2015
By
Monitor convergence during simulation studies in SAS

Ugh! Your favorite regression procedure just printed a warning to the SAS log. Something is wrong, and your attempt to fit a model to the data has not succeeded. A typical message is "WARNING: The validity of the model fit is questionable," perhaps followed by some additional diagnostic messages about […] The post Monitor convergence during simulation studies in SAS appeared first on The DO Loop.

Read more »

Video: Ten tips for simulating data with SAS

August 24, 2015
By
Video: Ten tips for simulating data with SAS

One of my presentations at SAS Global Forum 2015 was titled "Ten Tips for Simulating Data with SAS". The paper was published in the conference proceedings several months ago, but I recently recorded a short video that gives an overview of the 10 tips: If your browser does not support […] The post Video: Ten tips for simulating data with SAS appeared first on The DO Loop.

Read more »

Ten tips for simulating data with SAS

August 24, 2015
By
Ten tips for simulating data with SAS

One of my presentations at SAS Global Forum 2015 was titled "Ten Tips for Simulating Data with SAS". The paper was published in the conference proceedings several months ago, but I recently recorded a short video that gives an overview of the 10 tips: If your browser does not support […] The post Ten tips for simulating data with SAS appeared first on The DO Loop.

Read more »

She wants to be an airborne ranger

August 21, 2015
By
She wants to be an airborne ranger

I wanna be an airborne ranger, Live the life of guts and danger.* If you are an 80's movie buff, you might remember the scene in The Breakfast Club where Bender, the juvenile delinquent played by Judd Nelson, distracts the principal by running through the school singing this song. Recently, […] The post She wants to be an airborne ranger appeared first on The DO Loop.

Read more »

Correlations between groups of variables

August 19, 2015
By
Correlations between groups of variables

Typically a correlation analysis reports the correlations between all pairs of variables, including the variables with themselves. The resulting correlation matrix is square, symmetric, and has 1s on the main diagonal. But suppose you are interested in only specific combinations of variables. Perhaps you want the pairwise correlations between one […] The post Correlations between groups of variables appeared first on The DO Loop.

Read more »

Create heat maps with PROC SGPLOT

August 17, 2015
By
Create heat maps with PROC SGPLOT

When SAS 9.4m3 was released last month (including SAS/STAT and SAS/IML 14.1), I was happy to see that a HEATMAP statement had been added to the SGPLOT procedure. Although heat maps in the SAS/IML language have been available for several releases, you previously had to use the Graph Template Language […] The post Create heat maps with PROC SGPLOT appeared first on The DO Loop.

Read more »

The drunkard’s walk in 2-D

August 12, 2015
By
The drunkard’s walk in 2-D

Last month I wrote about how to simulate a drunkard's walk in SAS for a drunkard who can move only left or right in one direction. A reader asked whether the problem could be generalized to two dimensions. Yes! This article shows how to simulate a 2-D drunkard's walk. In […] The post The drunkard's walk in 2-D appeared first on The DO Loop.

Read more »


Subscribe

Email:

  Subscribe