topic Re: parallelizing do loop in SAS in SAS Programming

parallelizing do loop in SAS

Ramiro_iese — Fri, 06 Jan 2023 14:42:15 GMT

Is it possible to run a %do loop (in a macro) ussing parallel processing?

Re: parallelizing do loop in SAS

ballardw — Fri, 06 Jan 2023 16:07:16 GMT

This could well depend on what you mean by parallel processing.

Can you provide a description or details of what you are wanting to do.

Re: parallelizing do loop in SAS

yabwon — Fri, 06 Jan 2023 16:15:17 GMT

If you want to do a "parallel macro execution" in BASE SAS look up this tutorial:

https://pages.mini.pw.edu.pl/~jablonskib/SASpublic/Parallel-processing-in-BASE-SAS.sas

Bart

Re: parallelizing do loop in SAS

Ramiro_iese — Fri, 06 Jan 2023 16:28:17 GMT

I am new in SAS, but I am used to code in Julia.

There exist a library called "Threads". Then, for example, if you have a for loop from 1 to 12 and your computer has 4 cores, these process divides the computation between them and then it merges the results and shows it as it were calculated one by one

Re: parallelizing do loop in SAS

yabwon — Fri, 06 Jan 2023 16:39:19 GMT

BASE SAS is single threaded (in general) with some exceptions (like sorting with Proc Sort or Proc DS2's threads). There is no dedicated library/package for parallel processing.

If you have SAS Viya (with CAS engine) you can have "parallel" data step processing.

Bart

Re: parallelizing do loop in SAS

SASKiwi — Fri, 06 Jan 2023 21:55:37 GMT

Parallel processing in SAS usually means you run multiple SAS jobs at the same time, each in a separate SAS session. If you are running the same logic in each job, you need to split your input data so each SAS job does a different slice of data.

Typically you only parallel process to speed up slow run times. There is no point in doing it if your run times are acceptable. For example, I have a parallelised job that took around 14 hours to run sequentially, but now takes less than 4 hours, split into 4 parallel jobs all running at the same time.

Re: parallelizing do loop in SAS

LinusH — Tue, 10 Jan 2023 10:27:42 GMT

There's a concept called MP Connect (requires a SAS/CONNECT license).

In short you can spawn several child SAS sessions from a master SAS session.

One benefit is you can relatively easily orchestrate this using SAS code (e.g. do%), so you don't have to rely on OS functionality.

https://support.sas.com/rnd/scalability/connect/mp.html

https://documentation.sas.com/doc/en/pgmsascdc/9.4_3.5/connref/p1sszj6a6otsy2n1pnseg8vh98l8.htm