topic Re: Calculating distance between observations in SAS/IML Software and Matrix Computations

Calculating distance between observations

scrofungulus4 — Sun, 24 Mar 2013 05:41:04 GMT

I have a set of, say 36 observations and wish to calculate the distance matrix for these observations. Now I can do so with the use of a double do-loop, but this seems tedious (even though, for my purposes at this stage, computation time is negligible still). I read that the "distance" operator can be used in this way:

delta = distance(matrix, "L2");

for, say, the Euclidian distance. It seems like a nifty function, unfortunately on my SAS9.3 system, the log gives me an error saying "Invocation of unresolved module DISTANCE."

Anybody have an idea why this is?

Re: Calculating distance between observations

Rick_SAS — Sun, 24 Mar 2013 11:07:10 GMT

The DISTANCE function was introduced in SAS/IML 12.1, which was released as part of SAS 9.3M2 (the second maintenance releaase): See Support.sas.com

Re: Calculating distance between observations

Rick_SAS — Wed, 27 Mar 2013 10:25:57 GMT

Of course, you can still write your own distance function by using the SAS/IML language, as shown in the following article:
How to compute the distance between observations in SAS - The DO Loop